title: Lincoln's smile: ambiguities of the face in photography.
authors.forename: A
authors.initials: A
authors.lastname: Trachtenberg
mesh_terms: D005149:Facial Expression; D049672:History, 19th Century; D010551:Personality / Q000145:classification / Q000502:physiology; D010781:Photography / Q000266:history / Q000295:instrumentation / Q000379:methods; D014481:United States