@misc{fanger_the_hydrographic_1990, 
author={Fanger, H.-U.,Kappenberg, J.,Kuhn, H.,Maixner, U.,Milferstaedt, D.},
title={The hydrographic measuring system HYDRA},
year={1990},
howpublished = {book part},
note = {Online available at: \url{} (DOI). Fanger, H.; Kappenberg, J.; Kuhn, H.; Maixner, U.; Milferstaedt, D.: The hydrographic measuring system HYDRA. In: Michaelis, W. (Ed.): Estuarine water quality management: monitoring, modelling and research - Coastal and estuarine studies. Berlin: Springer. 1990. 211-216.}}