Researchr is a web site for finding, collecting, sharing, and reviewing scientific publications, for researchers by researchers.
Sign up for an account to create a profile with publication list, tag and review your related work, and share bibliographies with your co-authors.
Clarence A. Ellis. The Halting Problem for Probabilistic Context-Free Generators. Journal of the ACM, 19(3):396-399, 1972. [doi]