PLANCK: Systematic effects induced by periodic fluctuations of arbitrary shape A. Mennella, M. Bersanelli, C. Burigana, D. Maino, N. Mandolesi, G. Morgante and G. Stanghellini A&A, 384 2 (2002) 736-742 Published online: 15 March 2002 DOI: 10.1051/0004-6361:20020024