edited by Mildred F. Schamertz
McGraw-Hill, 1972
Buku Teks
edited by Mildred F. Schmertz
McGraw-Hill, 1972
Buku Referensi
Ojeda, Oscar Riera, author
Rockport Publishers, 1997
Buku Referensi
editors, George F. Thompson, Frederick R. Steiner
John Wiley & Sons, 1997
Buku Teks
Wright, Paul H., author
John Wiley & Sons, 1989
Buku Teks