1
2
Published 1989
3
Published 1992
4
by Scase
Published 1987
5
by Raj
Published 1990
6
Published 2004
7
8
9
by Phipps
Published 1994
10
by Levinson
Published 1993
11
by Fleishman
Published 1993
12
13
by Bygrave
Published 1994
14
15
by Griffiths
Published 2002
16
by Caplan
Published 1994
17
Published 1995
18
by Goss
Published 1991
19
by Remenyi
Published 1991
20
Published 1989