DeFalco, L. A., Fernandez, G. C. J., Nowak, R. S., (2007). Biological Invasions 9(3), 293-307. Springer Science + Business Media, Dordrecht, Netherlands. English language
Hunter, R. A., Wallace, A., Romney, E. M., (1978). Journal of Range Management 31(3), 199-203. English language