Winterowd, W. Ross
Harcourt Brace Jovanovich, 1981
Buku Teks
Penfield, Elizabeth, author
Scott, Foresman and Company, 1985
Koleksi Publik
Mcmahan, Elizabeth
McGraw-Hill, 1984
Buku Teks
Connelly, Mark, author
Wadsworth and Cengage Learning, 2013
Buku Teks
Sloane, Thomas O., author
Oxford University Press, 2001
Buku Referensi