compiled by S.K Baker
Oxford Publishing, 1984
Buku Referensi
Philip, George
George Philip and Son, 1983
Buku Referensi
Rapp, Stan
Erlangga, 1995
Buku Teks
Lenin, Vladimir I.
Foreign Languages Publishing House , [date of publication not identified]
Buku Teks
Rapp, Stan
McGraw-Hill , 1994
Buku Teks