Johannes Bauer
Springer, 2012
eBooks
Omrod, Jeanne Ellis, author
Pearson Education, Inc., 2009
Buku Teks
Jongkon Lee, author
Seoul National University, 2019
Artikel Jurnal
Topping, J.
Chapman and Hall , 1972
Buku Teks
Bloom, Benyamin S., author
McGraw-Hill, 1976
Buku Teks