Willis, Marjorie Canfield, author
J.B. Lippincott, 2008
Buku Teks
Ryan, William T.
Learning System Company, 1971
Buku Teks
Slavin, Albert, author
Holt Rinehart and Winston, 1972
Buku Teks
Ryan, William T.
Dew Jones Irwin, 1980
Buku Teks
Martin, E. Wainright
Illinois: Richard D Irwin, 1969
Buku Teks