Rettig, Stephen A. & Bortleson, Gilbert C. Limnological Study of Shasta Lake, Shasta County, California, with Emphasis on the Effects of the 1977 Drought, report, April 1983; (https://digital.library.unt.edu/ark:/67531/metadc967883/m1/1/: accessed August 21, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .