United States. Federal Communications Commission. FCC Record, Volume 4, No. 5, Pages 1965 to 2289, February 27 - March 10, 1989, book, March 1989; (https://digital.library.unt.edu/ark:/67531/metadc1684/m1/1/: accessed May 20, 2019), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .