Hill, G.A., author
Ginn, 1889
Buku Teks
Gibilisco, Stan, 1953-, author
McGraw-Hill, 2011
Buku Teks
Bowser, Edward A., author
D. Van Nostrand, 1893
Buku Teks
staff of Research and Education Association, Max Fogiel, director
California Research and Education Association, 1987
Buku Teks
Johson, Norman W, author
Cambridge University Press, 2018
Buku Teks