Roberts, Kate Louise, compiler
Grosset and Dunlap , 1940
Buku Referensi
Tremaine, Howard M., author
Howard W. Sams & Co., 1959
Buku Teks
editor L. Mary Barker
A & F Pears , 1949
Buku Referensi
Educational Book, 1951
Buku Teks
edited by Frank N. Magill
Harper & Brothers, 1958
Buku Referensi