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