A ring-like zone of strong radial gas motions in the disk of NGC 6181 O. K. Sil'chenko, A. V. Zasov, A. N. Burenkov and J. Boulesteix Astron. Astrophys. Suppl. Ser., 121 1 (1997) 1 Published online: 15 January 1997 DOI: 10.1051/aas:1997108