1
2
by Fisher
Published 1993
3
4
5
by Razali Mat Zin
Published 1990
6
7
by Chek Mat
Published 2003
8
Published 2000
9
by Reichheld
Published 2001
10
11
by Boyd
Published 1996
12
by Adair
Published 1984
13
by Maxwell
Published 1995
14
by Quigley
Published 1993
15
by Briner
Published 1996
16
by Razali Mat Zin
Published 1986
17
by Yeoh
Published 1995
18
19
20