Report [of the] International Musicological Society,
fo[u]rth congress, Basle, June 29-July 3, 1949.
Hrsg. von der Schweizerischen Musikforschenden Gesellschaft Ortsgruppe Basel.

APA Citation

International Musicological Society. Congress 1949 : Basel, S., Schweizerische Musikforschende Gesellschaft. Ortsgruppe Basel. (1950). Report [of the] International Musicological Society: fo[u]rth congress, Basle, June 29-July 3, 1949. Basel: Bärenreiter.

MLA Citation

International Musicological Society. Congress 1949 : Basel, Switzerland), and Schweizerische Musikforschende Gesellschaft. Ortsgruppe Basel. Report [of The] International Musicological Society: Fo[u]rth Congress, Basle, June 29-July 3, 1949. Basel: Bärenreiter, 1950.

Warning: These citations may not always be complete (especially for serials).