@article {36203,
	title = {13NMR characterization of humic matter present in different oil sands},
	volume = {7},
	year = {1989},
	pages = {477-505},
	publisher = {Petroleum Science and Technology},
	author = {Kotlyar, L. S. and Ripmeester, J. A. and Sparks, B. D.}
}
