1
2
by Nelsen, Harvey W., 1939-
Published 1989
3
Published 2003
4
Published 2001
5
6
7
by Lien Chan
Published 1994
8
by Henderson
Published 1999
9
10
by Latif
Published 2007
11
Published 1990
12
13
14
15
by Lo
Published 2004
16
Published 2000
17
by Wang
Published 2000
18
19
Published 1988
20
by Jackson
Published 1992