After I saw people, who have to take care of the references on their own, I am always glad that bibtex does that for me. After looking around for several month now, the program I like best for editing my bibtex database is kbibtex. It is really nice; the possibility to enter wrong things is relatively low and there are no UTF-8 problems. The roadmap looks also promising. It is a pity that it is not included in Debian yet.
Perhaps it can be quickened if someone can help with writing a good documentation (that's a hint for all of you who have some spare time ;) ).
Thomas also said to me on jabber that he would be happy if someone could make a code-review.
So a big thank you to Thomas Fischer for making my life more easy :)