эстонских

эстонских

The word "эстонских" in English means "Estonian" (genitive plural or accusative plural form).

In this sentence, 'эстонских' is an adjective in the genitive plural case, describing the origin of the 'картин' (paintings).

Я был на выставке эстонских картин.

I was at an exhibition of Estonian paintings.

Here, 'эстонских' is an adjective in the genitive plural case, modifying the noun 'друзей' (friends).

'Эстонских друзей мало, но они верные,' сказала она.

There are few Estonian friends, but they are faithful, she said.

In this instance, 'эстонских' is an adjective in the prepositional plural case, as required by the preposition 'об' (about), describing 'художниках' (artists).

Я читала книгу об эстонских художниках.

I read a book about Estonian artists.