Bitbucket Symbol
Autor: Guilherme Lima
Quelle: http://www.softicons.com/social-media-icons/flat-gradient-social-icons-by-guilherme-lima/bitbucket-icon

Codecademy Symbol
Autor: -
Quelle: http://a714.phobos.apple.com/us/r30/Purple/v4/01/a1/3d/01a13d32-c291-b7c0-2b0d-ae1615bba381/mzl.cuoisqnr.png

GitHub Symbol
Autor: GitHub
Quelle: https://github.com/logos

GitLab Symbol
Autor: GitLab
Quelle: https://about.gitlab.com/press/press-kit/#logos
Lizenz: https://creativecommons.org/licenses/by-nc-sa/4.0/

Stack Overflow Symbol
Autor: G. Pritiranjan Das
Quelle: http://www.softicons.com/social-media-icons/social-media-icons-by-g.-pritiranjan-das/stack-overflow-icon

Ubuntu Symbol
Autor: Martz90
Quelle: http://www.softicons.com/application-icons/circle-icons-by-martz90/ubuntu-icon

Wikipedia Symbol
Autor: Paul Robert Lloyd
Quelle: http://www.softicons.com/social-media-icons/social-media-icons-by-paul-robert-lloyd/wikipedia-icon