Erge, ThomasThomasErgeHoffmann, V.U.V.U.HoffmannKiefer, KlausKlausKiefer2022-03-032022-03-032001https://publica.fraunhofer.de/handle/publica/20036210.1016/S0038-092X(00)00143-2en621697The German experience with grid-connected PV-systemsjournal article