Herweg, Michael. 1991. Perfective and imperfective aspect and the theory of events and states. Linguistics 29. 996–1111.
@article{627,
author = {Herweg, Michael},
journal = {Linguistics},
key = {Herweg 1991},
pages = {996–1111},
title = {Perfective and imperfective aspect and the theory of events and states},
volume = {29},
year = {1991}
}