1. Billingsley, P.: Convergence of Probability Measures, (Wiley series in probability and mathematical statistics. Tracts on probability and statistics). New York: John Wiley & Sons, 1968
2. Boi, S., Capasso V.: Il comportamento aggregativo della specie Polyergus rufuscenslatr.: dalle osservazioni al modello matematico, Internal Report, Dipartimento di Matematica, Università di Milano, 1997
3. Boi, S., Capasso, V., Morale, D.: Modeling the aggregative behavior of ants of the species. Polyergus rufescens, Nonlinear Analysis: Real World Applications, I, 2000, pp. 163?176
4. Carillo, J.: Entropy solutions for nonlinear degenerate problems. Arch. Rat. Mech. Anal. 147, 269?361 (1999)
5. Diekmann, O., Gyllenberg, M., Thieme, H.R.: Lack of uniqueness in transport equations with a nonlocal nonlinearity. Math. Models Meth. Appl. Sci. 10, 581?592 (2000)