On Lingualism.com, we sell digital products only. Our books are available for purchase as PDF eBooks. But our books are also available in paperback on Amazon. On each book’s product page on our website, there is a link to Amazon in case you prefer to get a book in print. Previously, I was using ‘smart links’ which detected your geographic location and would direct you to your local Amazon website (Amazon.de if you are in Germany, for example). Recently, many of these smart links have stopped working (as the company behind them changed hands), so I’ve now added icons of national flags with links to those Amazon sites.