The Door to Time question

So, I'm a school librarian and one of my 5th grade students loves the books writen by Ulysses Moore (Pierdomenico Baccalario)! But, while reading it, he thinks he found a plot hole...
well, I myself have never read the books, so i promtly responded that he could try to write to the author asking about it (!) big mistake.. because now I cannot find an adress, twitter account, goodreads account nor anything where we could send the letter in the hopes Baccalario reads it..

My question is if you guys know anything related to the subject in question? do you know an address to which we can send the letter?

Best regards,
Marta, the librarian in big trouble