- ITIL®: https://www.axelos.com/best-practice-solutions/itil/what-is-itil
- PRINCE2®: https://www.prince2.com/uk/what-is-prince2
- BMC: http://www.bmc.com
- OMNINET: http://www.omninet.de/
- RDS Consulting GmbH: http://www.rds.de
- Hesse Consulting: https://www.hesse-consulting.de