21
by Gerber
Published 2008
22
by Blanchard
Published 2008
23
by Goldsmith
Published 2007
24
by Hutcheon
Published 1996
25
by PATTEN
Published 1995
26
by MAYER
Published 1998
27
by HISRICH
Published 1998
28
by KIMBRELL
Published 1992
29
by TACK
Published 1967
30
by TURNER
Published 2002
31
by Buzan
Published 2004
32
by COOPER
Published 2003
33
by Kennedy
Published 1999
34
by McCormack
Published 1989
35
by HISRICH
Published 2002
36
by BIRCH
Published 2000
37
by SHAW
Published 2006
38
by DOWNS
Published 1998
39
40