Zadeh, L., Toward a generalized theory of uncertainty (GTU)-an outline, Information Sciences 172, 1-40, 2005.
 Bede, B., and Gal, S.G., Almost periodic fuzzy- number-valued functions, Fuzzy 147, 385-403, 2004.
 Bede, B., and Gal, S. G., Generalizations of the differentiability of fuzzy- with applications to fuzzy differential equations, Fuzzy 151, 581-599, 2005.
 Dubois, D., and Prade, H., Fuzzy numbers: an overview, in: J. Bezdek (Ed.), Analysis of Fuzzy Information, CRC Press, 112-148, 1987.
 Wu, C., and Gong, Z., On Henstock. integral of fuzzy number-valued functions, I, Fuzzy sets and systems 120, 523-532, 2001.
 Gal, S. G., Approximation theory in fuzzy setting, in: G.A. Annastassiou (Ed.), Handbook of Analytic. Computational Methods in Applied Mathematics, chapman & Hall/CRC press, 617-666, 2000.
 Chalco-Cano, Y., Roman-Flores, on new solutions of fuzzy differential equations, Chaos Solutions and Fractals, In press, 2006.
 Puri, M., and Ralescu, D., Differentials of fuzzy functions, Journal of Mathematical Analysis and Applications 91, 552-558, 1983.