21
by Blake, David H.,
Published 1983
22
by Rodrik, Dani
Published 1999
23
by Ovenden, Keith
Published 1989
24
by Wriggins, W. Howard, 1918-
Published 1978
25
by Gill, Stephen, 1950 -
Published 1988
26
by Fawcett, J. E. S, 1913-
Published 1977
27
Published 1978
28
by Pirages, Dennis
Published 1978
29
by Frey, Bruno S.
Published 1984
30
31
Published 1998
32
by Panic, M, 1935-
Published 1988
33
34
by Longworth, Richard C.
Published 1999
35
Published 1998
36
by Olson, Gary L.
Published 1984
37
by Snider, Delbert A.
Published 1979
38
by Bhattacharya, Debesh
Published 1984
39
Published 2004
40
by Asher, Robert E, 1910-
Published 1957