title: EFFECT OF VARIOUS FACTORS ON THE UTILIZATION OF NITROGEN AND IRON BY SPIRODELA POLYRHIZA (L.) SCHLEID.
authors.affiliation: DEPARTMENT OF AGRONOMY, UNIVERSITY OF MASSACHUSETTS, AMHERST, MASSACHUSETTS.
authors.forename: E H
authors.initials: EH
authors.lastname: Bitcover
authors.forename: D H
authors.initials: DH
authors.lastname: Sieling