1. Hukuhara, M., Integration des applications measurables dont la valeur est un compact convexe, Funkcial. Ekvac., 1967, vol. 10, pp. 205–223.
2. De Blasi, F.S. and Ievorlino, F., Equazioni differentiali con soluzioni a valore compatto convesso, Bol. Unione Mat. Ital., 1967, vol. 2, nos. 4–5, pp. 491–501.
3. Diamond, P. and Kloeden, P., Metric Spaces of Fuzzy Sets. Theory and Applications, River Edge, New Jork: World Scientific, 1994.
4. Gnana Bhaskar, T. and Shaw, M., Stability results for set difference equations, Dyn. Syst. Appl., 2004, vol. 13, no. 2, pp. 479–485.
5. Lakshmikantham, V., Bhaskar, T.G., and Vasundhara Devi, J., Theory of Set Differential Equations in Metric Spaces, Cambridge: Cambridge Sci. Publ., 2006.