Simpson J L, Alford M A, Carter K D, Keech R V
Department of Ophthalmology & Visual Sciences, University of Iowa Hospitals and Clinics, Iowa City 52242-1091, USA.
J Pediatr Ophthalmol Strabismus. 1999 Mar-Apr;36(2):90-1. doi: 10.3928/0191-3913-19990301-09.