1
by Acs, Zoltan J.
Published 2016
2
Published 2017
3
4
Published 2019
5
Published 2017
6
Published 2018
7
Published 2018
8
9
10
Published 2001
11
Published 2001
12
Published 2003
13
by Juma,
Published 2005
14
15
16
Published 2007
17
Published 2005
18
Published 2007
19
Published 2012
20
Published 2012