 Other Mahasamghika sources are the Mahavastu and (possibly) the Śālistamba Sūtra, both of which also contains phrases and doctrines that are found in the Sthavira canons.Further exemplary studies are the study on descriptions of "liberating insight" by Lambert Schmithausen, the overview of early Buddhism by Tilmann Vetter, the philological work on the four truths by K.R.Norman, the textual studies by Richard Gombrich, and the research on early meditation methods by Johannes Bronkhorst.