Alert Citizens of Texas, Inc. [Letter from H. Clem Mueller, M.D. of Alert Citizens of Texas, Inc. to "Concerned Texan"], letter, [1983, 1984]; (https://digital.library.unt.edu/ark:/67531/metadc177453/m1/1/: accessed December 19, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .