1
by Kaplan, 1935-
Published 1995
2
by Covey
Published 1990
3
by Skopec
Published 1991
4
5
by Zuker
Published 1991
6
by Robbins
Published 1986
7
by Ainon
Published 2003
8
by Thomas
Published 1992
9
10
by Robbins
Published 2003
11
by Sharma
Published 2006
12
by Kanoy
Published 2013