R. R. Bowker Company, 1982
Buku Referensi
R. R. Bowker Company, 1982
Buku Referensi
R. R. Bowker Company, 1982
Buku Referensi
Robert M. Hutchins, Mortimer J. Adler, editors in chief
Encyclopaedia Britannica, Inc., 1963
Buku Referensi
Americana Corporation, 1960
Buku Referensi