edited by Isaac Kramnick
[publisher not identified], 1969
Buku Teks SO
Wanlass, Lawrence C.
Appleton-Century-Crofts, 1953
Buku Teks
Sabine, George H.
Henry Holt, 1950
Buku Teks
Sabine, George H.
George G. Harrap, 1959
Buku Teks SO
Sabine, George H.
Henry Holt , 1954
Buku Teks SO