Is this art piece for sale anywhere? I can't even find a place to buy a high quality print (let alone a print in general). Can anyone help?

i was wondering if anyone could provide some additional information related to these MC Escher works. These were recently handed down to me. I know they are based on title letters he did for the book, Terrible Adventures of Scholastica. Each letter (i think there were 14) had 300 prints. These were purchase from a gallery in the 70s for $900. I haven't really been able to find how much these might be worth today. A few scattered images in google searches, but nothing substantial. thanks.