Wanlass, Lawrence C.
Appleton-Century-Crofts, 1953
Buku Teks
Allen, J. W.
Methuen, 1951
Buku Teks
Allen, J. W.
University Paprebacks, 1960
Buku Teks
Gettell, Raymond G.
Appleton-Century-Crofts, 1928
Buku Teks
Canning, Joseph
Routledge, 1996
Buku Teks