Before revision: He is best known for his methods—popularly called Ferberization—that purports to teach infants to learn how to fall asleep on their own, which are described in his book Solve Your Child's Sleep Problems (first edition 1985).
After revision: controversial<ref name="babycenter">He is best known for his methods—popularly called Ferberization—that purports to teach infants to learn how to fall asleep on their own, which are described in his book Solve Your Child's Sleep Problems (first edition 1985).