Bagaev V.S. ,     Galkina T.I. ,     Gogolin O.V. Excitons in Ge at High Concentrations and Low Temperatures. X-th Intern. Conf. on Physics of Semiconductors. Proc. 17-21 Aug.1970. Cambridge, Massachusetts / Ed.S.P.Keller, J.C.Hensel, F.Stern. , с. P.500-504