Which art dealers currently handle original lithographs (not posters) by Rodo Gabriela Boulanger?

I have a 1973 Lithograph by Gabriela Rodo Boulanger. It looks like an
original. It shows six faces and arms (only) and each one is playing an instrument. I have searched and not found this particular one. Would someone know a bit more or perhaps guide me to another source to find the name and value on this please? Kind regards

Can you tell me the value of a stone signed lithograph (or seriograph?) of Boulanger’s “Apres le tournei”