1
by Prosser
Published 2010
2
by Peale
Published 2003
3
by Schuller
Published 1990
4
by Garlow
Published 2007
5
by Covey
Published 2004
6
by Chu
Published 2007
7
8
by Gladwell
Published 2013
9
by Prosser
Published 2005
10
11
by Sharma, Robin S.
Published 2006
12
by Canfield
Published 2007
13
by Peale
Published 1982
14
by Fletcher
Published 2000
15
by COVEY
Published 1998
16
17
by POWELL
Published 1991
18
by HAY
Published 1990
19
20
by NIVEN
Published 2005