Lerner, Harriet Goldhor, author
Harper and Row, 1989
Buku Referensi
Orr, Marjorie
Abdi Tandur, 1994
Buku Teks
by Peter Senge , Art Kleiner..[et.al.]
Curreney Doubleday , 1999
Buku Teks
Walker, Richard, author
De Agostini, 1996
Buku Teks
Jusuf Sutanto, author
Kompas, 2009
Buku Teks