Printed Book vs Digital- Which Footprint Should I Pick?

While in NZ I came across an article comparing the ecological footprint of a Tablet eReader with the printed Book. I've found another article by the New York Times. It seems the book comes out ahead unless you read lots of books, then the tablet might just have the advantage. 40 books equate to just over 3 a month so I might just qualify in needing an Tablet eReader!
The last line in the article pleased me no end
"The most ecologically virtuous way to read a book starts by walking to your local library!"
The article can be found at https://smartairmedia.com/content/blogs/blog-sections/digital-media/item/book-ereader-enviro.

I wonder what the comparison with an eInk Reader might be? That might definitely give the book a run for its ecological footprint - enough to justify a couple of eReaders over 2-3 years perhaps??

This is always supposing we in Australia get appropriate laws regarding recycling of eWaste and not sending it OS to India/China or another third world country.

For seniors there is a definite benefit to buying a tablet eReader - flexible print sizing. See this article also in the NY times blog.

Unfortunately for us Aussies, buying books from Book Depository/Amazon and sending to Australia would also be regarded as a bad ecological idea.
Perhaps that's why its cheaper in $$ and human designed economics. 
Its a pity as I rather like browsing online and sending books to my house. After a day at the library my feet are too sore to drive to the nearest large bookstore. And my bookshelves are far too full already which is another good reason to borrow from my library and not buy.