1) Source: BSI-A-CS 004 | version 1.00 dated April 12, 2012 (downloaded May 23, 2013)
2) Source: BDEW (downloaded May 23, 2013)
3) Source: BDEW (downloaded May 23, 2013)
4) Source: ENISA (downloaded May 24, 2013)
5) Source: BSI Standard 100-1, Version 1.5, 2008 (downloaded July 15, 2014)