 A small amount of data was collected by early researchers such as Samuel Barrett; however, extensive work was not carried out until Abraham M. Halpern, in the 1940s, collected a number of Southern Pomo words and texts as part of a larger effort to collect data on all the Pomo languages.Halpern published one article, "Southern Pomo h and ʔ and Their Reflexes", which dealt with aspects of Southern Pomo phonology.Halpern's unpublished notes are currently housed at the University of California, Berkeley.