The IRAM key-project: Small-scale structure of pre-star forming regions - III. Influence of and correction for the error beam pick-upF. Bensch, J.-F. Panis, J. Stutzki, A. Heithausen and E. FalgaroneA&A, 365 2 (2001) 275-284DOI: https://doi.org/10.1051/0004-6361:20000475