diff --git a/CHANGES.txt b/CHANGES.txt
index 44c93cc..2255bc0 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -1,9 +1,12 @@
 2.1.0 (TBD)
 
 Added:
+- Add the option to get Planetary Variable subscription results as a CSV file ().
+- A subscription_request.planetary_variable_source function has been added
+  (#976).
 - The subscription_request.build_request function has a new option to clip to
-  the subscription's source geometry. This is a preview of the default
-  behavior of the next version of the Subscriptions API.
+  the subscription's source geometry. This is a preview of the default behavior
+  of the next version of the Subscriptions API (#971).
 
 2.0.3 (2023-06-28)
 
diff --git a/planet/cli/subscriptions.py b/planet/cli/subscriptions.py
index f97671e..6816d15 100644
--- a/planet/cli/subscriptions.py
+++ b/planet/cli/subscriptions.py
@@ -162,10 +162,13 @@ async def get_subscription_cmd(ctx, subscription_id, pretty):
                        "success"]),
     multiple=True,
     default=None,
-    callback=lambda ctx,
-    param,
-    value: set(value),
+    callback=(lambda ctx, param, value: set(value)),
     help="Select subscription results in one or more states. Default: all.")
+@click.option('--csv',
+              'csv_flag',
+              is_flag=True,
+              default=False,
+              help="Get subscription results as an unpaged CSV file.")
 @limit
 # TODO: the following 3 options.
 # –created: timestamp instant or range.
@@ -178,13 +181,20 @@ async def list_subscription_results_cmd(ctx,
                                         subscription_id,
                                         pretty,
                                         status,
+                                        csv_flag,
                                         limit):
     """Gets results of a subscription and prints the API response."""
     async with subscriptions_client(ctx) as client:
-        async for result in client.get_results(subscription_id,
-                                               status=status,
-                                               limit=limit):
-            echo_json(result, pretty)
+        if csv_flag:
+            async for result in client.get_results_csv(subscription_id,
+                                                       status=status,
+                                                       limit=limit):
+                click.echo(result)
+        else:
+            async for result in client.get_results(subscription_id,
+                                                   status=status,
+                                                   limit=limit):
+                echo_json(result, pretty)
 
 
 @subscriptions.command()  # type: ignore
diff --git a/planet/clients/subscriptions.py b/planet/clients/subscriptions.py
index 1e44485..99a93e2 100644
--- a/planet/clients/subscriptions.py
+++ b/planet/clients/subscriptions.py
@@ -1,7 +1,7 @@
 """Planet Subscriptions API Python client."""
 
 import logging
-from typing import AsyncIterator, Optional, Set
+from typing import AsyncIterator, Literal, Optional, Sequence
 
 from planet.exceptions import APIError, ClientError
 from planet.http import Session
@@ -58,7 +58,7 @@ class SubscriptionsClient:
             self._base_url = self._base_url[:-1]
 
     async def list_subscriptions(self,
-                                 status: Optional[Set[str]] = None,
+                                 status: Optional[Sequence[str]] = None,
                                  limit: int = 100) -> AsyncIterator[dict]:
         """Iterate over list of account subscriptions with optional filtering.
 
@@ -216,16 +216,21 @@ class SubscriptionsClient:
 
     async def get_results(self,
                           subscription_id: str,
-                          status: Optional[Set[str]] = None,
+                          status: Optional[Sequence[Literal[
+                              "created",
+                              "queued",
+                              "processing",
+                              "failed",
+                              "success"]]] = None,
                           limit: int = 100) -> AsyncIterator[dict]:
         """Iterate over results of a Subscription.
 
-        Note:
+        Notes:
             The name of this method is based on the API's method name. This
             method provides iteration over results, it does not get a
             single result description or return a list of descriptions.
 
-        Args:
+        Parameters:
             subscription_id (str): id of a subscription.
             status (Set[str]): pass result with status in this set,
                 filter out results with status not in this set.
@@ -252,7 +257,6 @@ class SubscriptionsClient:
             resp = await self._session.request(method='GET',
                                                url=url,
                                                params=params)
-
             async for sub in _ResultsPager(resp,
                                            self._session.request,
                                            limit=limit):
@@ -263,3 +267,45 @@ class SubscriptionsClient:
             raise
         except ClientError:  # pragma: no cover
             raise
+
+    async def get_results_csv(self,
+                              subscription_id: str,
+                              status: Optional[Sequence[Literal[
+                                  "created",
+                                  "queued",
+                                  "processing",
+                                  "failed",
+                                  "success"]]] = None,
+                              **kwargs) -> AsyncIterator[str]:
+        """Iterate over rows of results CSV for a Subscription.
+
+        Notes:
+            The name of this method is based on the API's method name. This
+            method provides iteration over results, it does not get a
+            single result description or return a list of descriptions.
+
+        Parameters:
+            subscription_id (str): id of a subscription.
+            status (Set[str]): pass result with status in this set,
+                filter out results with status not in this set.
+            TODO: created, updated, completed, user_id
+
+        Yields:
+            str: a row from a CSV file.
+
+        Raises:
+            APIError: on an API server error.
+            ClientError: on a client error.
+        """
+        url = f'{self._base_url}/{subscription_id}/results'
+        params = {'status': [val for val in status or {}], 'format': 'csv'}
+
+        # Note: retries are not implemented yet. This project has
+        # retry logic for HTTP requests, but does not handle errors
+        # during streaming. We may want to consider a retry decorator
+        # for this entire method a la stamina:
+        # https://github.com/hynek/stamina.
+        async with self._session._client.stream('GET', url,
+                                                params=params) as response:
+            async for line in response.aiter_lines():
+                yield line
diff --git a/planet/subscription_request.py b/planet/subscription_request.py
index 391f168..f0e7d8d 100644
--- a/planet/subscription_request.py
+++ b/planet/subscription_request.py
@@ -13,7 +13,7 @@
 # the License.
 """Functionality for preparing subscription requests."""
 from datetime import datetime
-from typing import Any, Dict, Optional, List, Mapping
+from typing import Any, Dict, Optional, List, Literal, Mapping
 
 from . import geojson, specs
 from .exceptions import ClientError
@@ -49,7 +49,7 @@ def build_request(name: str,
                   delivery: Mapping,
                   notifications: Optional[Mapping] = None,
                   tools: Optional[List[Mapping]] = None,
-                  clip_to_source=False) -> dict:
+                  clip_to_source: Optional[bool] = False) -> dict:
     """Construct a Subscriptions API request.
 
     The return value can be passed to
@@ -73,12 +73,12 @@ def build_request(name: str,
             behavior.
 
     Returns:
-        A Python dict representation of a Subscriptions API request for
-        a new subscription.
+        dict: a representation of a Subscriptions API request for
+            a new subscription.
 
     Raises:
-        ClientError when a valid Subscriptions API request can't be
-        constructed.
+        ClientError: when a valid Subscriptions API request can't be
+            constructed.
 
     Examples:
     ```python
@@ -152,27 +152,34 @@ def catalog_source(
     end_time: Optional[datetime] = None,
     rrule: Optional[str] = None,
 ) -> dict:
-    """Catalog subscription source.
+    """Construct a Catalog subscription source.
+
+    The return value can be passed to
+    [planet.subscription_request.build_request][].
 
     Parameters:
-    item_types: The class of spacecraft and processing level of the
-        subscription's matching items, e.g. PSScene.
-    asset_types: The data products which will be delivered for all subscription
-        matching items. An item will only match and deliver if all specified
-        asset types are published for that item.
-    geometry: The area of interest of the subscription that will be used to
-        determine matches.
-    start_time: The start time of the subscription. This time can be in the
-        past or future.
-    filter: The filter criteria based on item-level metadata.
-    end_time: The end time of the subscription. This time can be in the past or
-        future, and must be after the start_time.
-    rrule: The recurrence rule, given in iCalendar RFC 5545 format. Only
-        monthly recurrences are supported at this time.
+        item_types: The class of spacecraft and processing level of the
+            subscription's matching items, e.g. PSScene.
+        asset_types: The data products which will be delivered for all
+            subscription matching items. An item will only match and
+            deliver if all specified asset types are published for that
+            item.
+        geometry: The area of interest of the subscription that will be
+            used to determine matches.
+        start_time: The start time of the subscription. This time can be
+            in the past or future.
+        filter: The filter criteria based on item-level metadata.
+        end_time: The end time of the subscription. This time can be in
+            the past or future, and must be after the start_time.
+        rrule: The recurrence rule, given in iCalendar RFC 5545 format.
+            Only monthly recurrences are supported at this time.
+
+    Returns:
+        dict: a representation of a subscription source.
 
     Raises:
-        planet.exceptions.ClientError: If start_time or end_time are not valid
-            datetimes
+        ClientError: if a source can not be
+            configured.
     """
     if len(item_types) > 1:
         raise ClientError(
@@ -212,6 +219,86 @@ def catalog_source(
     return {"type": "catalog", "parameters": parameters}
 
 
+def planetary_variable_source(
+    var_type: Literal["biomass_proxy",
+                      "land_surface_temperature",
+                      "soil_water_content",
+                      "vegetation_optical_depth"],
+    var_id: str,
+    geometry: Mapping,
+    start_time: datetime,
+    end_time: Optional[datetime] = None,
+) -> dict:
+    """Construct a Planetary Variable subscription source.
+
+    Planetary Variables come in 4 types and are further subdivided
+    within these types. See [Subscribing to Planetary
+    Variables](https://developers.planet.com/docs/subscriptions/pvs-subs/#planetary-variables-types-and-ids)
+    for details.
+
+    The return value can be passed to
+    [planet.subscription_request.build_request][].
+
+    Note: this function does not validate variable types and ids.
+
+    Parameters:
+        var_type: one of "biomass_proxy", "land_surface_temperature",
+            "soil_water_content", or "vegetation_optical_depth".
+        var_id: a value such as "SWC-AMSR2-C_V1.0_100" for soil water
+            content derived from AMSR2 C band.
+        geometry: The area of interest of the subscription that will be
+            used to determine matches.
+        start_time: The start time of the subscription. This time can be
+            in the past or future.
+        end_time: The end time of the subscription. This time can be in
+            the past or future, and must be after the start_time.
+
+    Returns:
+        dict: a representation of a subscription source.
+
+    Raises:
+        ClientError: if a source can not be
+            configured.
+
+    Examples:
+        ```python
+        >>> source = planetary_variable_source(
+        ...     "soil_water_content",
+        ...     "SWC-AMSR2-C_V1.0_100",
+        ...     geometry={
+        ...         "type": "Polygon",
+        ...         "coordinates": [[[37.791595458984375, 14.84923123791421],
+        ...                         [37.90214538574219, 14.84923123791421],
+        ...                         [37.90214538574219, 14.945448293647944],
+        ...                         [37.791595458984375, 14.945448293647944],
+        ...                         [37.791595458984375, 14.84923123791421]]]
+        ...     },
+        ...     start_time=datetime(2021, 3, 1)
+        ... )
+        >>> request = build_request(source=source, ...)
+        ```
+    """
+    # TODO: validation of variable types and ids.
+
+    parameters = {
+        "id": var_id,
+        "geometry": geojson.as_geom(dict(geometry)),
+    }
+
+    try:
+        parameters['start_time'] = _datetime_to_rfc3339(start_time)
+    except AttributeError:
+        raise ClientError('Could not convert start_time to an iso string')
+
+    if end_time:
+        try:
+            parameters['end_time'] = _datetime_to_rfc3339(end_time)
+        except AttributeError:
+            raise ClientError('Could not convert end_time to an iso string')
+
+    return {"type": var_type, "parameters": parameters}
+
+
 def _datetime_to_rfc3339(value: datetime) -> str:
     """Converts the datetime to an RFC3339 string"""
     iso = value.isoformat()

diff --git a/tests/integration/test_subscriptions_api.py b/tests/integration/test_subscriptions_api.py
index e1ea533..7046c02 100644
--- a/tests/integration/test_subscriptions_api.py
+++ b/tests/integration/test_subscriptions_api.py
@@ -128,7 +128,12 @@ def result_pages(status=None, size=40):
 # must disable the default.
 res_api_mock = respx.mock(assert_all_called=False)
 
-# 1. Request for status: created. Response has three pages.
+# 1. CSV results
+res_api_mock.route(
+    M(url__startswith=TEST_URL), M(params__contains={'format': 'csv'})).mock(
+        side_effect=[Response(200, text="id,status\n1234-abcd,SUCCESS\n")])
+
+# 2. Request for status: created. Response has three pages.
 res_api_mock.route(
     M(url__startswith=TEST_URL),
     M(params__contains={'status': 'created'})).mock(side_effect=[
@@ -136,12 +141,12 @@ res_api_mock.route(
         for page in result_pages(status={'created'}, size=40)
     ])
 
-# 2. Request for status: queued. Response has a single empty page.
+# 3. Request for status: queued. Response has a single empty page.
 res_api_mock.route(M(url__startswith=TEST_URL),
                    M(params__contains={'status': 'queued'})).mock(
                        side_effect=[Response(200, json={'results': []})])
 
-# 3. No status requested. Response is the same as for 1.
+# 4. No status requested. Response is the same as for 1.
 res_api_mock.route(M(url__startswith=TEST_URL)).mock(
     side_effect=[Response(200, json=page) for page in result_pages(size=40)])
 
@@ -276,6 +281,18 @@ async def test_get_results_success():
         assert len(results) == 100
 
 
+@pytest.mark.anyio
+@res_api_mock
+async def test_get_results_csv():
+    """Subscription CSV fetched, has the expected items."""
+    async with Session() as session:
+        client = SubscriptionsClient(session, base_url=TEST_URL)
+        results = [res async for res in client.get_results_csv("42")]
+        import csv
+        rows = list(csv.reader(results))
+        assert rows == [['id', 'status'], ['1234-abcd', 'SUCCESS']]
+
+
 paging_cycle_api_mock = respx.mock()
 
 # Identical next links is a hangup we want to avoid.
diff --git a/tests/integration/test_subscriptions_cli.py b/tests/integration/test_subscriptions_cli.py
index 3f9feef..5fe4b42 100644
--- a/tests/integration/test_subscriptions_cli.py
+++ b/tests/integration/test_subscriptions_cli.py
@@ -306,3 +306,11 @@ def test_request_catalog_success(invoke, geom_geojson):
     ])
     assert json.loads(result.output) == source
     assert result.exit_code == 0  # success.
+
+
+@res_api_mock
+def test_subscriptions_results_csv(invoke):
+    """Get results as CSV."""
+    result = invoke(['results', 'test', '--csv'])
+    assert result.exit_code == 0  # success.
+    assert result.output.splitlines() == ['id,status', '1234-abcd,SUCCESS']
diff --git a/tests/unit/test_subscription_request.py b/tests/unit/test_subscription_request.py
index b22983b..69c5bae 100644
--- a/tests/unit/test_subscription_request.py
+++ b/tests/unit/test_subscription_request.py
@@ -346,3 +346,23 @@ def test_toar_tool_success():
 
     expected = {"type": "toar", "parameters": {"scale_factor": 12345}}
     assert res == expected
+
+
+def test_pv_source_success(geom_geojson):
+    """Configure a planetary variable subscription source."""
+    # NOTE: this function does not yet validate type and id.
+    # The nonsense values are intended to fail when the function does
+    # add validation.
+    source = subscription_request.planetary_variable_source(
+        "var1",
+        "VAR1-abcd",
+        geometry=geom_geojson,
+        start_time=datetime(2021, 3, 1),
+        end_time=datetime(2021, 3, 2),
+    )
+
+    assert source["type"] == "var1"
+    params = source["parameters"]
+    assert params["id"] == "VAR1-abcd"
+    assert params["geometry"] == geom_geojson
+    assert params["start_time"].startswith("2021-03-01")

Support for upcoming csv timeseries subscription results
**Is your feature request related to a problem? Please describe.**

With the introduction of PVs to the subscription API we are also supporting timeseries in csv format.

This is available on api.planet.com/subscriptions/v1 but not yet documented offically.

**Describe the solution you'd like**

I would like to use the `format=csv` option of the subscription API. 

Example request:

```
https://api.planet.com/subscriptions/v1/<uuid>/results?format=csv
```

**Additional context**

[Internal document](https://docs.google.com/document/d/1dj8qPeHy4a7vR6Mu2HVuO2bfPaDU_m4y9ExBC_RFpXY/edit#heading=h.pc8fh9xlg1ef) explaining the endpoint.


tests/integration/test_subscriptions_api.py::test_get_results_csv tests/integration/test_subscriptions_cli.py::test_subscriptions_results_csv tests/unit/test_subscription_request.py::test_pv_source_success
tests/integration/test_subscriptions_api.py::test_list_subscriptions_failure tests/integration/test_subscriptions_api.py::test_list_subscriptions_success[status0-100] tests/integration/test_subscriptions_api.py::test_list_subscriptions_success[status1-0] tests/integration/test_subscriptions_api.py::test_list_subscriptions_success[None-100] tests/integration/test_subscriptions_api.py::test_create_subscription_failure tests/integration/test_subscriptions_api.py::test_create_subscription_success tests/integration/test_subscriptions_api.py::test_cancel_subscription_failure tests/integration/test_subscriptions_api.py::test_cancel_subscription_success tests/integration/test_subscriptions_api.py::test_update_subscription_failure tests/integration/test_subscriptions_api.py::test_update_subscription_success tests/integration/test_subscriptions_api.py::test_get_subscription_failure tests/integration/test_subscriptions_api.py::test_get_subscription_success tests/integration/test_subscriptions_api.py::test_get_results_failure tests/integration/test_subscriptions_api.py::test_get_results_success tests/integration/test_subscriptions_api.py::test_list_subscriptions_cycle_break tests/integration/test_subscriptions_cli.py::test_subscriptions_list_options[options0-100] tests/integration/test_subscriptions_cli.py::test_subscriptions_list_options[options1-100] tests/integration/test_subscriptions_cli.py::test_subscriptions_list_options[options2-1] tests/integration/test_subscriptions_cli.py::test_subscriptions_list_options[options3-2] tests/integration/test_subscriptions_cli.py::test_subscriptions_list_options[options4-0] tests/integration/test_subscriptions_cli.py::test_subscriptions_create_failure tests/integration/test_subscriptions_cli.py::test_subscriptions_create_success[--{"name": tests/integration/test_subscriptions_cli.py::test_subscriptions_create_success[{"name": tests/integration/test_subscriptions_cli.py::test_subscriptions_bad_request[--{0: tests/integration/test_subscriptions_cli.py::test_subscriptions_bad_request[{0: tests/integration/test_subscriptions_cli.py::test_subscriptions_cancel_failure tests/integration/test_subscriptions_cli.py::test_subscriptions_cancel_success tests/integration/test_subscriptions_cli.py::test_subscriptions_update_failure tests/integration/test_subscriptions_cli.py::test_subscriptions_update_success tests/integration/test_subscriptions_cli.py::test_subscriptions_get_failure tests/integration/test_subscriptions_cli.py::test_subscriptions_get_success tests/integration/test_subscriptions_cli.py::test_subscriptions_results_failure tests/integration/test_subscriptions_cli.py::test_subscriptions_results_success[options0-100] tests/integration/test_subscriptions_cli.py::test_subscriptions_results_success[options1-100] tests/integration/test_subscriptions_cli.py::test_subscriptions_results_success[options2-1] tests/integration/test_subscriptions_cli.py::test_subscriptions_results_success[options3-2] tests/integration/test_subscriptions_cli.py::test_subscriptions_results_success[options4-0] tests/integration/test_subscriptions_cli.py::test_request_base_success tests/integration/test_subscriptions_cli.py::test_request_catalog_success tests/unit/test_subscription_request.py::test_build_request_success tests/unit/test_subscription_request.py::test_build_request_clip_to_source_success tests/unit/test_subscription_request.py::test_build_request_clip_to_source_failure tests/unit/test_subscription_request.py::test_catalog_source_success tests/unit/test_subscription_request.py::test_catalog_source_featurecollection tests/unit/test_subscription_request.py::test_catalog_source_invalid_start_time tests/unit/test_subscription_request.py::test_amazon_s3_success tests/unit/test_subscription_request.py::test_azure_blob_storage_success tests/unit/test_subscription_request.py::test_google_cloud_storage_success tests/unit/test_subscription_request.py::test_oracle_cloud_storage_success tests/unit/test_subscription_request.py::test_notifications_success tests/unit/test_subscription_request.py::test_notifications_invalid_topics tests/unit/test_subscription_request.py::test_band_math_tool_success tests/unit/test_subscription_request.py::test_band_math_tool_invalid_pixel_type tests/unit/test_subscription_request.py::test_clip_tool_success tests/unit/test_subscription_request.py::test_clip_tool_invalid_type tests/unit/test_subscription_request.py::test_file_format_tool_success tests/unit/test_subscription_request.py::test_file_format_tool_invalid_format tests/unit/test_subscription_request.py::test_harmonize_tool_success tests/unit/test_subscription_request.py::test_harmonize_tool_invalid_target_sensor tests/unit/test_subscription_request.py::test_reproject_tool_success tests/unit/test_subscription_request.py::test_reproject_tool_invalid_kernel tests/unit/test_subscription_request.py::test_toar_tool_success