Allen, Don L. Periodontics for the dental hygienist / Don L. Allen, Walter T. M cFall [and] Grover C. Hunter. - 3rd. ed. - Philadephia : Lea & Febiger , 1980. - ix, 277 p. : ill. Subjects--Topical Terms: Periodontics--------Dentistry--------Hygiene-------- National Library of Medicine Call No.: WU 240 / Al53p 1980