Author,Title,Journal,ISSN,Publisher,Date,Volume,Number,Page,URL,URL(DOI) MAXWELL CA,A chalcone and two related flavonoids released from alfalfa roots induce nod genes of Rhizobium meliloti,Plant Physiol.,,,1989,91,,842-847,https://cir.nii.ac.jp/crid/1574231875268055936,