@misc{callies_analysing_covariance_2000, 
author={Callies, U., Petersen, W.},
title={Analysing Covariance Structures in Water-Quality Data},
year={2000},
howpublished = {conference lecture: Sheffield (GB);},
note = {Callies, U.; Petersen, W.: Analysing Covariance Structures in Water-Quality Data. TIES / SPRUCE 2000, Current Environmental Issues: Quantitative Methods. Sheffield (GB), 2000.}}