pubmed:affiliation |
Epidemiology Branch, Division of Epidemiology, Statistics & Prevention Research, National Institute of Child Health & Human Development, Rockville, MD 20852, USA. gb156i@nih.gov
|
pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.,
Research Support, N.I.H., Extramural
|