Bybee et al. 1994

Bybee, Joan L., Revere Perkins & William Pagliuca. 1994. The evolution of grammar: Tense, aspect and modality in the languages of the world. Chicago: The University of Chicago Press.

@book{bybee_evolution_1994,
  address    = {Chicago},
  author     = {Bybee, Joan L. and Perkins, Revere and Pagliuca, William},
  publisher  = {The University of Chicago Press},
  title      = {The evolution of grammar: Tense, aspect and modality in the languages of the world},
  year       = {1994},
  shorttitle = {The evolution of grammar}
}