Grigoriev, Nikolai Mikhailovich, the value of work
 

Help determine the value of his works Grigorieva, NM
1880-1943.
Enclose, "Park Cafe CDKA," 1936, oil on canvas, 68h48.

THIS TOP 10 WORK HUDOZhNIKA.Dannye taken from this site.
At the rink in a Moscow park (1)|On the rink. Moscow Park ( 2)
( 5378 GBP)
Hockey players and skaters on the ice
( 2400 EUR)

Clock Tower in Moscow
( 1584 USD)
In Moscow
(20 000 RUR)
orchestra
(20 000 RUR)
on the carousel
(20 000 RUR)
At the Lake Imandra
(600 USD)
Still Life with Decanter
(600 USD)
roundabout
(15 000 RUR)
roundabout
(15 000 RUR)

As I understand about skating in a Moscow park, this value (5378 GBP) had a very long time (like 2002).
In the gallery of pictures Shishkin data were evaluated as early as 1 -1.5 million (Lot 134 Auction 100).

So I'm trying to understand the overall trend for this artist.

The question remains how to evaluate this zhudozhnika.