Keplerian discs around post-AGB stars: a common phenomenon? S. De Ruyter, H. Van Winckel, T. Maas, T. Lloyd Evans, L. B. F. M Waters and H. Dejonghe A&A, 448 2 (2006) 641-653 Published online: 24 February 2006 DOI: 10.1051/0004-6361:20054062