Text in periodical Westerkamp, Hildegard. – «Acoustic ecology and the Zone of Silence». – Musicworks. – No. 31 (Spring 1985). – Interview with Norbert Ruebsaat. – P. 8-9.
Text in periodical Westerkamp, Hildegard. – «Wilderness lake». – Musicworks. – No. 15 (Spring 1981). – Interview with R. Murray Schafer. – P. 20-21.