The National cyclopedia of American biography; index :
permanent series (numbered vols.), current series (lettered vols.)

APA Citation

(1975). The National cyclopedia of American biography; index: permanent series (numbered vols.), current series (lettered vols.). [Rev.]. Clifton, N. J.: James T. White.

MLA Citation

The National Cyclopedia of American Biography; Index: Permanent Series (numbered Vols.), Current Series (lettered Vols.). [Rev.]. Clifton, N. J.: James T. White, 1975.

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