Holdsworth, Ruth, author
Macmillan, 1982
Buku Teks
Dennis, Lorraine Bradt, author
WB. Saunders, 1967
Buku Teks
Lindgran, Henry Clay
John Wiley & Sons, 1966
Buku Teks
Kalish, Richard A., author
Wadsworth, 1966
Buku Teks
Miles, Matthew B., author
Teacher College Columbia Univ., 1981
Buku Teks