E
[EH86] E. Allen Emerson and Joseph Y. Halpern. "Sometimes" and "Not Never" Revisited: On Branching versus Linear Time Temporal Logic. Journal of the ACM 33(1):151-178. ACM Press, January 1986. 
@article{jacm33(1)-EH,
  author =              {Emerson, E. Allen and Halpern, Joseph Y.},
  title =               {{"}{S}ometimes{"} and {"}Not Never{"} Revisited:
                         On~Branching versus Linear Time Temporal Logic},
  publisher =           {ACM Press},
  journal =             {Journal of the~ACM},
  volume =              {33},
  number =              {1},
  pages =               {151-178},
  year =                {1986},
  month =               jan,
}
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