Pigou, A.C. (Arthur Cecil), author
Macmillan, 1956
Buku Teks
Fisher, Ronald C., author
Routledge, 2016
Buku Teks
Fisher, Ronald C., author
Scott, Foresman, 1988
Buku Teks
Prest, A.R., author
English Language Book Society, 1974
Buku Teks
Musgrave, Richard A., author
McGraw-Hill, 1983
Buku Teks