Painting Grabar

[Жар-птица]

Say, here I am, for example, faced with the picture "Ryabinka" Grabar. I think everybody saw it, they know where the original hangs). Painting my same is now in a private collection, it turns out that Grabar drew pockmark these occasions. Expertise does not have, most likely it is the original owner was a friend of Grabar, etc. And really there to sell it, making art history expert and only?