Vellas, Francois
Macmillan Press, 1995
Buku Teks
Gadjah Mada University Press, 1992
Buku Teks
Henky Hermantoro, author
Aditri, 2011
Buku Teks
Made Handijaya Dewantara, author
The Ary Suta Center, 2018
Artikel Jurnal
Gartner, William C.
Van Nostrand Reinhold , 1996
Buku Teks