Santayana, George, author
Charles Scribner's Sons, 1945
Buku Teks
Johnson, Spencer, author
Harper Collins, 2004
Buku Teks
Burr, Vivien, author
Psychology Press, 2002
Buku Teks
Mearns, Dave, author
Sage Publications, 2003
Buku Teks
Casemore, Roger
Sage Publications, 2006
Buku Teks