The Berreyesa Family can be found in many of California's early records, records that can sometime be accessed very easily, and sometimes not. Some of these records are on the internet, and contain a wealth of information, though not everything is on the web. One source that the Berreyesa family is mentioned in, is the "Relacion" by Antonio Berryesa, an interview by Thomas Savage, about the murder of Jose de los Reyes Berreyesa and the de Harro twins. This interview is all handwritten, and is in Spanish. An English version is available through the Bancroft Library, by interlibrary loan, the call number is BANC MSS C-D 44. Books written about the family, such as the well known book, Berreyesa: The Rape of the Mexican Land Grant, Rancho Cañada de Capay, by Eftimeos Salonites, are a great resource as well.
With brand new internet site such as the Early California Population Project, things are getting easier for doing research in the California Missions. Also, for the Peralta family, Mission 2000, run by the Tumacácori National Historical Park, is a great source for the missions of the Pimeria Alta (southern Arizona, northern Sonora).
For the Berreyesa Researchers who are researching the Nasario Antonio Berreyesa branch, the Solano County Genealogical Society is another great site to check. for the Jose de los Reyes Berryesa branch, as well as for the Nasario Antonio branch, the Santa Clara County Historical & Genealogical Society is another great site to check.
There are many other great sources out there, like the microfilm found in the Family History Library in Salt Lake City, Utah. One in particular, The Berryessa family from the province of Sinaloa, Mexico, microfilm number 442, is nothing but a whole role of microfilm on the Berryessa.
There are many other sources out there, just waiting to be found, the real trick is finding them!