All the references in the book are included here, with DOI / ISBN numbers and links to the papers or books where they are available.
DOI, digital object identifier, is a unique reference for scientific papers which helps locate them.
Many books, especially older ones, are available online on archive.org
https://www.ethicalbooksearch.com is a good place to source second hand books
https://www.tinyecohomelife.com/second-hand-books-online-ethical-sellers has other bookseller recommendations