Anna's Wikipedia entry is here, and a link dealing with both sisters is here.
Anna could vary her style when called for. Some murals done in the 1930s are busy (as most murals should be) and painted in a mannered way. Her portrait work, on the other hand, was usually solidly, strikingly done, making use of smoothed, slightly simplified surfaces on her subjects' faces, hands, etc.
This is not Anna's usual style, but a credible website states that this is her work.
Posthumous portrait of the discoverer of Penicillin.