@article {1988,
	title = {Variational inequalities for the biharmonic operator with variable obstacles.},
	journal = {Ann. Mat. Pura Appl. (4)  153  (1988), 203-227 (1989)},
	number = {SISSA;50/87/M},
	year = {1988},
	publisher = {SISSA Library},
	url = {http://hdl.handle.net/1963/531},
	author = {Gianni Dal Maso and Gabriella Paderni}
}
