Translated from 'Beiträge zur Kryptogamenflora der Schweiz', Band 11. Bern: Büchler, 1954 & 1962.
Keys to the genera of amerospored and didymospored pyrenomycetes by J.A. von Arx. ISBN 0851990037. Published by Commonwealth Mycological Institute in 1969. Publication and catalogue information, links to buy online and reader comments.