I can clarify on Roginsky. In 60-ies. He either did not endorse on the face or put a signature block letters, large letters: actually, it was more a label than a signature - it is part of the composition (as at the Kazan station, who recently hung), destroying the illusion of space. Then, in the 70-and 80-ies. He did not put a signature, inodna signature - very small, less noticeable as possible - bear a dry, pencil or flamasterom - that he had to do with the sale of services at the request of the buyer. Then, in the 90-ies. - Work on cardboard, signature and date marked on the reverse side. It was only from about 1995, he again began to put a signature on the face, or in the lower right corner, or, as suggested by the Amateur, the edge itself, which go under the frame.
Here are some examples:
- Still Life with Vegetables, 1964, private collection, Paris
- Venus on a stool, 1965, meeting Grigorishin
- Primus, 1965, Museum Zimmerly - Glasha catch!
- Shelves, 1978, private collection, Paris - the signature dry flamasterom, it must be far to seek

- Trolley, 2000, meeting of the company Ruhrgas - signed in the lower right corner, unnoticed tozhe
Unsigned work does not show - because they do not look at that: D