1
2
3
Published 2007
4
Published 2007
5
by Noble
Published 1994
6
7
by Thompson
Published 1987
8
9
Published 2008
10
11
by Weaver
Published 1948
12
by Spengler
Published 2002
13
by Schweitzer
Published 1987
14
by Wilson
Published 1937
15
by Boorstin
Published 1998
16
by Boorstin
Published 1993
17
18
19
by Wallace-Murphy
Published 2006
20