Who signed RS
 

I can not find the author's paintings. RS

As a signature-monogram "RS", and the style of painting (including the characteristic perspective distortion), in my opinion, may suggest the authorship of Swedish artist Ragnar Sandberg (Ragnar Sandberg, 1902 - 1972). It is - quite a famous artist in the network a lot of reproductions of his works. But, of course, I would not take his claim authorship unambiguously.