GERARD JENNHWA CHANG2018-09-102018-09-101996http://www.scopus.com/inward/record.url?eid=2-s2.0-0030367240&partnerID=MN8TOARShttp://scholars.lib.ntu.edu.tw/handle/123456789/321006The L(2, 1)-labeling problem on graphsjournal article