Douglas, S. E. Plastid evolution: origins, diversity, trends. Current Opinion in Genetics & Development. December 1998, 8 (6): 655–661. PMID 9914199. doi:10.1016/S0959-437X(98)80033-6.
Keeley, J. E.; Rundel, P. W. Fire and the Miocene expansion of C4 grasslands. Ecology Letters. 2005, 8 (7): 683–690. doi:10.1111/j.1461-0248.2005.00767.x.
Douglas, S. E. Plastid evolution: origins, diversity, trends. Current Opinion in Genetics & Development. December 1998, 8 (6): 655–661. PMID 9914199. doi:10.1016/S0959-437X(98)80033-6.