Astley, W. G. (1985). "The two ecologies: population and community perspectives on organizational evolution." Administrative Science Quarterly, 30: 224-241.

Carrol, G. R. and M. T. Hannan (1989). "Density dependence in the evolution of poplations of newspaper organizations." American Sociological Review, 54: 524-548.

DiMaggio vs Hannan & Freeman on Emergence of New Organizational Forms (exam question by Keith Rollag)

Hannan, M. T. and J. Freeman (1989). Organizational Ecology,. Cambridge, Harvard University Press.