PT Unknown AU Yagoubov, P Kroug, M Merkel, H Kollberg, E Schubert, J Hubers, HW Svechnikov, S Voronov, B Gol'tsman, G Wang, Z TI Hot electron bolometric mixers based on NbN films deposited on MgO substrates SE Inst. Phys. Conf. Ser. PY 1999 BP 687 EP 690 VL 167 PI Barcelona, Spain ER