@article {30869,
	title = {Geochemical significance of chemical composition and ESR properties of asphaltenes in crude oils from Alberta, Canada},
	volume = {41},
	year = {1977},
	pages = {567-580},
	publisher = {Geochimica et Cosmochimica Acta},
	author = {Elofson, R. M. and Schulz, K. F. and Hitchon, Brian}
}
