Links
[1] https://ifross.org/?q=faq/what-kind-source-code-do-i-have-publish-under-gnu-gpl
[2] http://gpl-violations.org/faq/sourcecode-faq.html
[3] https://ifross.org/?q=category/faq-ordnung/iii-gnu-general-public-license-gpl-version-2
[4] https://ifross.org/?q=wann-muss-eigenentwickelte-software-unter-gpl-lizenziert-werden
[5] https://ifross.org/?q=en/when-does-independently-developed-software-have-be-licensed-under-gpl
[6] https://ifross.org/?q=welche-pflichten-bestehen-beim-rein-internen-einsatz-unter-gplv2-lizenzierter-software
[7] https://ifross.org/?q=en/what-are-obligations-involved-internal-use-software-licensed-under-gplv2
[8] https://ifross.org/?q=welche-pflichten-bestehen-bei-verbreitung-veraenderten-versionen-unter-gplv2-lizenzierter-software
[9] https://ifross.org/?q=en/what-obligations-are-involved-distributing-changed-versions-software-licensed-under-gplv2
[10] http://www.ifross.eu/wann-muss-eigenentwickelte-software-unter-gpl-lizenziert-werden
[11] https://ifross.org/?q=welche-pflichten-bestehen-bei-verbreitung-unter-gplv2-lizenzierter-software
[12] https://ifross.org/?q=en/what-obligations-are-involved-distributing-software-licensed-under-gplv2
[13] https://ifross.org/?q=welche-rechte-koennen-durch-gpl-erworben-werden
[14] https://ifross.org/?q=en/what-rights-can-be-acquired-gpl
[15] http://www.ifross.eu/darf-ich-open-source-software-nutzen-welche-nutzungsrechte-erwerbe-ich
[16] https://ifross.org/?q=was-gpl
[17] https://ifross.org/?q=en/what-gpl
[18] http://www.gnu.de/documents/gpl-2.0.de.html
[19] http://www.gnu.de/documents/gpl-3.0.de.html