1
2
by Ratnam
Published 2004
3
Published 1995
4
Published 2007
5
6
by Chalmers
Published 1990
7
Published 2009
8
Published 2009
9
by Brase
Published 2013
10
by Giordano
Published 2014
11
12
by Gilat
Published 2005
13
by Abdullah
Published 2005
14
by Steinhardt
Published 2007
15
by Baykoucheva
Published 2015
16
17
by Verstraete
Published 2008
18
19
by Gustafson
Published 1980
20
by William
Published 2001