" The development of quantum mechanics in the 1920s was truly remarkable. There were several centers for physics research ; Cambridge, Gottingen, Munchen, Berlin, Copenhagen, Zurich and Leyden. In this study, more than 110 European physicists appear with their teacher-student relationship. Many of these scientists were born between 1900 and 1908. Consequently, they were un their twenties in the late 1920s. Pauli called quantum mechanics “Knaben Physik” (Boy’s Physics) "