@book{7793,
	author = {Jensen, Charles A.},
	title = {Seasonal nitrification as influenced by crops and tillage.},
	publisher = {Govt. print. off.,},
	year = {1910.},
	series = {U. S. Dept. of agriculture. Bureau of plant industry. Bulletin},
	address = {Washington,},
	url = {http://hdl.loc.gov/loc.gdc/scd0001.00027565359}
}