See also: FRANKLY SPEAKING: ZAPPA THE COMPOSER (1940 - 1993) - The Influence of Varèse and the Evolution of Classical Pop
To read more about Wulf Zendik, go HERE. (There is also a little information on Wikipedia.)
The Zappa interview is on pages 7-11. It was originally published in Ecolibrium Interviews magazine, issue #19 (1985).
Some parts are a little blurry, but everything is readable.
Click to enlarge (then click again, if need be).