Tyner, Kathy L., author
WCB, 1993
Buku Teks
by John E. Brewton ... [et al.]
Laidlaw Brother, 1957
Buku Teks
Farrell, Edmund James ... [et al.]
Scott, Foresman, 1976
Buku Teks
Gregg, Donald C.
Allyn and Bacon, 1961
Buku Teks
Carter, Ronald
Cambridge Cambridge University , 1987
Buku Teks