1. Department of Maternal and Child Health, Carolina Global Breastfeeding Institute, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
2. Department of Maternal and Child Health, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
3. Department of Obstetrics and Gynecology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
4. Health Sciences Library, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
5. School of Nursing, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.