Maria or Manya Sklodowska?!?!

So I have this project thing for French, where I have to do a project on something or someone, or in my case, someones, related to France. I'm working with this other kid, who should be at my house in like 15 minutes to work on the project with me. Our topic? Marie and Pierre Curie. My sister actually recently did a project on Marie Curie, she had to do a book report. I am not doing a book report, just a 5 minute presentation thing. So, in the book she was assigned, it was stated that Marie Curie was born Manya Sklodowska, however, in every single internet source, plus 1 book source I've read, it says that she was born Maria Sklodowska. Which is right? Manya, or Maria? I think Maria, because I've gotten it from several trustworthy sources, including the official Nobel Prize website. But why would a published book have the wrong information? Especially a published book in an elementary school library??? That makes no sense to me. I'd say she was born Maria but some sources say Manya, but I've just gotten it from too many sources. The thing is, no one ever called her Maria, her family and friends all called her Manya, since, like, the day she was born. Book, I think you need to get your facts right. Also, every website and/or book that said she was born Maria mentioned that she was called Manya. See, I don't get this. All of the info in a nonfiction biography book technically are supposed to be correct!!! But in this case it's not? I don't know. This makes no sense to me. Books should have the right information in them, that's what I know. So for now, I will continue to think Maria, although my little sister and my mom think otherwise. Let me know what you think. Ta ta! -Ali