Letter: Duration of breast-feeding.
D000367:Age Factors; D001942:Breast Feeding; D003906:Developing Countries; D005260:Female; D006801:Humans; D007223:Infant; D007227:Infant Nutritional Physiological Phenomena; D007231:Infant, Newborn; D012423:Rural Health; D013997:Time Factors; D014886:Weaning