@article {38869,
	title = {In Situ upgrading of heavy oils and bitumen by propane deasphalting : the vapex process. SPE Productions Operations Symp. Oklahoma City, Oklahoma, U. S. A., March 21 -23, 1993},
	year = {1993},
	author = {Mokrys, I. J. and Butler, R. M.}
}
