(EHRHART, W.D., Roger Martin, and others.) BETZ, Daniel R., edited by books & textbook
The Pub 5 - Spring 1980 (Volume 2, Number 1)
(EHRHART, W.D., Roger Martin, and others.) BETZ, Daniel R., edited by
Ansuda Publications /1980T Paperback
(EHRHART, W.D., Roger Martin, and others.) BETZ, Daniel R., edited by
Ansuda Publications /1980T Paperback