KAUFMANN A., 1985, Introduction to Fuzzy Arithmetic
KENDALL M. G., 1977, The Advanced Theory of Statistics 1
10.1080/09537289008919311
WANG J. H., 1988, International Industrial Engineering Conference Proceedings, 30
10.1080/00207549008942731
10.1016/0020-0255(75)90036-5
10.1016/0022-247X(68)90078-4