Antonietta Brandeis Self Portrait

I recently purchased a drawing that is supposedly a self portrait. She appears quite young. On the verso there is a character sketch with some critiques in what looks like French as well as the artist working on her signature over and over again in different styles. I know that early on Antonietta studied under the Czech artist Karel Javurek in Prague. Karel studied under Thomas Coutoure in France and often there was French influence in his paintings. It helps to understand why there is French on a piece created by an artist who painted in Italy and the Czech Republic. Does it seem plausible that this piece was done while under the tutelage of Karel Javurek? How do you put a value to a piece like this? I have never purchased a piece like this so any help or guidance is very appreciated. Thank you.

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What is the provenance of the portrait. What type of documentation do you have?

Unfortunately all I have is the picture. I just purchased it at one of the high end Florida auction houses.