Margaret Stark Head in the moon painting, how much would this be worth?

Thank you for your answers!

 

This is a different painting but sold for $2,250

https://www.liveauctioneers.com/item/14708996_margaret-stark-american-1915-1988

 

Information about Margaret Stark... although she died in 1988, apparently her output after the 1960s was very little?

http://fineestateart.com/artists/margaret_stark

 

http://www.askart.com/artist/Margaret_Stark/5051395/Margaret_Stark.aspx

http://www.artnet.com/artists/margaret-stark/past-auction-results

I'm not a member of these sites, so I can't get prices, but still... fun to look. You have a real treasure there!

 

Here's more examples of her work:

http://www.galeriadionisbennassar.com/fondos-galeria/margaret-stark/

Debora