Graham, Sheila Y.
Harcourt Brace Jovanovich , 1972
Buku Teks
Jaderstrom, Susan, author
McGraw-Hill Glencoe, 2003
Buku Teks
Woodhall, Victoria
Hodder & Stoughton, 1992
Buku Teks
Gummere, John Flagg
Scott, Foresman and Company, 1955
Buku Teks
Langan, John, 1942-, author
McGraw-Hill, 1994
Buku Teks