Jg. Bak, AN INTERPOLATION THEOREM AND A SHARP FORM OF A MULTILINEAR FRACTIONAL-INTEGRATION THEOREM, Proceedings of the American Mathematical Society, 120(2), 1994, pp. 435-441
We prove a sharp interpolation theorem for Orlicz spaces with the Luxe
mburg norm. As a corollary we obtain a sharp form of an exponential in
tegrability theorem, due to Grafakos, for the multilinear fractional i
ntegration operator. This generalizes a theorem of Adams.