bibtex-autokey-title-terminators

bibtex-autokey-title-terminators is a variable defined in `bibtex.el'.
Its value is

"[.!?:;]\\|--"

Documentation:
Regexp defining the termination of the main part of the title.
Case of the regexps is ignored. See `bibtex-generate-autokey' for details.

You can customize this variable.