Differential of Fuzzy Functions with Two Variables and Fuzzy Wave Equations
YU Lan-fang,MA Shu-hua,SONG Ze-cheng,TENG Wen-kai
Journal of Hebei University (Natural Science Edition) . 2009, (5): 466 -468 .  DOI: 10.3969/j.issn.1000-1565.2009.05.006