@book{25364,
	author = {Bigham, J.M, and Ciolkosz, E. J,},
	title = {Soil Color: Proceeding of a Symposium Sponsored by Divisions S-5 and S-9 of the Soil Society of america in San Antonio, Texas, 21-26 oct.1990 /},
	publisher = {Soil Science Society of America,},
	year = {1993.},
	series = {SSSA Special Publication Number 31},
	address = {Madison :}
}