1
Published 2009
Ministry of Regional Development, Poland

2
Published 2007
Statistics Poland

3
Published 2017
OECD Publishing

4
by Hawley, David E.
Published 2012
Helion

5
by Bluttman, Ken
Published 2012
Helion

6
by Chromatic
Published 2012
Helion

7
by Cumming, Andrew
Published 2012
Helion

8
by Perry, Bruce W.
Published 2012
Helion

9
by Mitchell, Lorna Jane
Published 2015
Helion

10
by Liberty, Jesse
Published 2012
Helion

11
by Liberty, Jesse
Published 2012
Helion

14
by Ceceri, Kathy
Published 2015
Helion

15
by Seshadri, Shyam
Published 2018
APN Promise

16
by Green, Brad, Seshadri, Shyam
Published 2014
Helion

17
by Seshadri, Shyam, Green, Brad
Published 2016
Helion

18
by Albahari, Joseph
Published 2012
Helion

19
by Albahari, Joseph, Albahari, Ben
Published 2018
Wydawnictwo Helion

20
by MacDonald, Matthew
Published 2012
Helion