Is 'Sometime' Sometimes Better Than 'Always'? Intermittent Assertions in Proving Program Correctness

@inproceedings{Manna-Waldinger:ICSE76,
  author    = {Zohar Manna and
               Richard J. Waldinger},
  title     = {Is {'Sometime'} Sometimes Better Than {'Always'?} Intermittent Assertions in Proving Program Correctness},
  booktitle = {ICSE},
  pages     = {32--39},
  publisher = {{IEEE} Computer Society},
  year      = {1976},
}