Text in periodical Zapf, Donna. – «Inside the soundscape : the compositions of Hildegard Westerkamp». – Musicworks. – No. 15 (Spring 1981). – P. 5-8.
Text in periodical Zapf, Donna. – «The World Soundscape Project revisited». – Musicworks. – No. 15 (Spring 1981). – P. 4-5.