Collier's encyclopedia : volume 21
Macmillan Educational Company, 1990
Buku Referensi
Collier's encyclopedia : volume 22
Macmillan Educational Company, 1990
Buku Referensi
Collier's encyclopedia : volume 24
Macmillan Educational Company, 1990
Buku Referensi
Collier's encyclopedia; Volume 4
Macmillan, 1990
Buku Referensi
Collier's encyclopedia; Volume 2
Macmillan, 1990
Buku Referensi