Holdsworth, Roger F., author
Brithis Institute of Management, 1972
Buku Teks
Shackelford, James F., author
CRC Press, , 1995
Buku Referensi
Artikel Jurnal
Ioannis Nikolaou and Janneke K. Oostrom, edited
Psychology Press, 2015
Buku Teks
Dale, Margaret, author
Crest Publishing House, 2001
Buku Teks