Angulo, Jaime de
Shelter Publications, Inc., 1973
Buku Teks
Sage Publications, Inc, 2006
Majalah, Jurnal, Buletin
Schulz, Rockwell, author
McGraw-Hill, 1976
Buku Teks
Schulz, Rockwell, author
McGraw-Hill, 1983
Buku Teks
Abrams, Charles, author
MIT Press, 1964
Buku Teks