Pears cyclopedia
editor L. Mary Barker
A & F Pears , 1949
 Buku Referensi
Tremaine, Howard M.
Audio cyclopedia
Howard W. Sams & Co., 1959
 Buku Teks
Coyne television cyclopedia : a practical reference book on television receivers and reception / General editors Bennett W. Cooke, Silas C. Narland and Raymond A. Snyder
Educational Book, 1951
 Buku Teks
Cyclopedia of world authors
edited by Frank N. Magill
Harper & Brothers, 1958
 Buku Referensi
Hoyt, Robert S.
Europe in the middle ages / Robert S. Hoyt
Harcourt, Brace & World, 1957
 Buku Teks