Bhola Nath Moitra Bijay Baran Pal A Fuzzy Goal Programming Approach for Solving Bilevel Programming Problems. 91-98 2002 conf/afss/2002 AFSS http://link.springer.de/link/service/series/0558/bibs/2275/22750091.htm db/conf/afss/afss2002.html#MoitraP02