@misc{theopold_doublecavity_etalon_1993, 
author={Theopold, F. A., Weitkamp, C., Michaelis, W.},
title={Double-Cavity etalon in the near infrared},
year={1993},
howpublished = {GKSS report},
note = {Theopold, F.; Weitkamp, C.; Michaelis, W.: Double-Cavity etalon in the near infrared. Optics Letters. 1993. vol. 18, no. 3, 253-254.}}