"The agency was forced to suspend its operations by Chinese authorities for a number of reasons, one of which was for missing three years of annual checks.In 1903, German philosopher Carl Buttenstedt published his marriage guidebook ""Die Glücksehe – Die Offenbarung im Weibe, eine Naturstudie"" ("The Marriage of Happiness – The Revelation in the Woman, a study from nature"), in which he described and recommended the lactational amenorrhea method (LAM) as a form of contraception and natural family planning that also deepens the relationship between wife and husband.