I am offering you this interview with Dr. Pamela Douglas, author of the book The Little Discontented Baby Book and the NDC Possums sleep-support program for families. She is the one who trained me on this topic.
Sleep is a topic that comes up very frequently in breastfeeding support meetings and lactation consultations, with questions about how to put the baby to sleep without the breast, about multiple awakenings, and anxiety about the lack of sleep, for both the mother and the baby.