Nachajon R V, Rutstein R M, Rudy B J, Collins M H
Division of Pulmonology, Children's Hospital of Philadelphia, University of Pennsylvania, USA.
Pediatr Pulmonol. 1997 Oct;24(4):292-5. doi: 10.1002/(sici)1099-0496(199710)24:4<292::aid-ppul9>3.0.co;2-m.