Cataligent is one of the leading providers of web-based software for controlling projects. Since the last 20 years, we have accrued several happy clients. We are headquartered in Dusseldorf (Germany), with another office in Cologne (Germany), and one in Noida (India).
Trello is a collaboration tool that organizes your projects into boards. In one glance, Trello tells you what's being worked on, who's working on what, and where something is in a process.
J. Smith, S. Bohner, and D. McCrickard. ACM-SE 43: Proceedings of the 43rd annual Southeast regional conference, page 300--305. New York, NY, USA, ACM, (2005)