Published: Vol. 1- Apr. 1940-
Physical Description: v. : ill., ports. ; 28 cm.
Microfilms of vols. 1-34 are available from University Microfilms.
Publication Frequency: Quarterly, 1942-
ISSN: 0025-9357
Finding Aid: Vols. 1-10, 1940-49 with v. 10; Vols. 11-20, 1950-59 (issued as v. 20, no. 4); Vols. 41-50, 1980-89 (issued as supplement to v. 50, no. 4).