Text in periodical Hays, Ron. – «Synthesizer & symphony». – Prime Time. – Vol. 3, no. 5 (Apr. 1973). – P. 10-11, 14.
Archive document : Correspondence / Letter Hays, Ron. – [Letter to Woody Vasulka]. – March 18th, 1973 [(sic)]. – [1] p. – Included in the file entitled «Hays, Ron».