Pawel Urzyczyn. During Cannot be Expressed by After . J. Comput. Syst. Sci., 32(1):97-104, 1986.
@article{Urzyczyn86, title = { During Cannot be Expressed by After }, author = {Pawel Urzyczyn}, year = {1986}, researchr = {https://researchr.org/publication/Urzyczyn86}, cites = {0}, citedby = {0}, journal = {J. Comput. Syst. Sci.}, volume = {32}, number = {1}, pages = {97-104}, }