Hobbs, Donald A., author
John Wiley & Sons, 1982
Buku Teks
Horton, Paul B., author
McGraw-Hill , 1984
Buku Teks
Kropotkin, Petr
Extending Horizons Books , 1955
Buku Teks
Appleton-Century-Crofts , 1967
Buku Teks
Schoorl, J.W.
Gramedia , 1982
Buku Teks