I am a writer. The same nonfiction books are available on both Kobo (at free $0) and Amazon (setting to free $0). All of them are my original works, and the first editions of these books uploaded are complete with more updates to come in later editions for both online and offline. Sometimes, I quote myself but there is no excerpt, and it is clearly introduced as a quotation and a reference to my own book. Quotations to other academic books as reference are cited with book title, author and the published date, and I intend to use APA citation format for future updates on the books on much later editions.