Haspelmath, Martin. 1990. The grammaticization of passive morphology. Studies in Language 14. 25–72.
@article{haspelmath1990, author = {Haspelmath, Martin}, journal = {Studies in Language}, key = {Haspelmath 1990}, number = {1}, pages = {25–72}, title = {The grammaticization of passive morphology}, volume = {14}, year = {1990} }