63 v. : ill. ; 28 cm.
Irregular
Vols. not issued consecutively.
Some v. issued in revised ed.
Vol. 15 issued in 2 parts.
Vol. for 1984 has both a letter and a number, N-63, and includes v. N. of Current volume.
Vol. 1-v. N-63.
Single-Volume General Biographical Reference Works