Balekjian, W.H.
Oceana Publications, Inc., 1967
Buku Teks
Oceana Publications Inc. , 1971
Buku Teks
Rubin, Seymour J.
John Hopkins Press , 1956
Buku Teks
Nwogugu, E.I.
Manchester University Press , 1965
Buku Teks
Mcdermott, Richard T.
Lexing Publishing, 2000
Buku Teks