Marriot, Bety Bowers
McGraw-Hill, 1997
Buku Referensi
Eccleston, Charles H.
CRC Press, Taylor & Francis Group, 2011
Buku Teks
Unesco-Unep International Environment Education Programme. National Institute of Educational Planning and Administration , 1988
Buku Teks
National Institute of Educational Planning and Administration , 1985
Buku Teks
Canter, Larry W.
McGraw-Hill, 1977
Buku Teks