Bradford, A. Frederick
Longmans, Geen and Co. , 1933
Buku Teks
Trescott, Paul B.
McGraw-Hill , 1965
Buku Teks
Trescoot, Paul B.
McGraw-Hill , 1960
Buku Teks
Shaw, Edward S.
Richard D. Irwin, 1950
Buku Teks
Bradford, Frederick A.
Longmas Green and Co. , 1939
Buku Teks