@misc{petersen_process_identification_2001, 
author={Petersen, W.,Bertino, L.,Callies, U.,Zorita, E.},
title={Process identification by principal component analysis of river water-quality data},
year={2001},
howpublished = {journal article},
note = {Online available at: \url{} (DOI). Petersen, W.; Bertino, L.; Callies, U.; Zorita, E.: Process identification by principal component analysis of river water-quality data. Ecological Modelling. 2001. vol. 138, no. 1 - 3, 193-213.}}