Some water, sir?

[U-niks]

Yes ... This is not a quiz, but a real puzzle!
Here are my thoughts.

I learned work on the fragments:
8 Emile Bernard
9 Gustav Klimt
10 Georgia O'Keeffe
12 Henri Matisse
15 Nicolas de Stael
20 William Turner

After some thought and decided to check that:
2 Sisley
4 marks
6 Hockney
11 Sulfur
13 Vlaminck
14 Nolde
18 Edward Hopper

I suspect that:
1 - Cezanne (long stroke, a Derain - shorter)
5 - Gauguin (he has a similar fragments in other works)
7 - Rouault (who else has used a violet).

Bonnard, Van Gogh, Monet and Derain to shame svomu not identified. : confused:

I hope the experts will help ...