Epidemiology of Menopause: Demographics, Environmental Influences, and Ethnic and International Differences in the Menopausal Experience The authors are indebted to the following collaborators in the study of the natural history of the menopause for their contributions to this work: Drs. Barbara Abrams, Shelley Adler, Gladys Block, Maradee Davis, Bruce Ettinger, Bill Lasley, Marion Lee, Marianne O'Neill Rasor, Steven Samuels, Helen Schauffler, Barbara Sommer, and Barbara Sternfeld.