N.A.Tikhonov

The stellar content of the ring in NGC 660

Ras, V. Hagen-Thorn, S. A. Observatory, 2004, astro-ph/0404286.

The Stellar Content of the Polar Rings in the Galaxies NGC 2685 and NGC 4650A

V.A.Hagen-Thorn, G.M.Karataeva, N.A.Tikhonov, 2003, astro-ph/0312566.