Because the book series is still relatively new, there isn't a huge amount of scholarly literature about it. But there is some! And because the books have been read widely, there are a number of interviews, book reviews, and general interest articles about the books.
I would recommend either searching for the book title - "my brilliant friend" (the quotation marks make the whole phrase stay together, rather than looking for the individual words) or the author's name. - elena ferrante.