https://bdef-book.com/resources.html 2026-06-03T14:02:15.041Z https://bdef-book.com/about.html 2026-06-03T12:52:23.241Z https://bdef-book.com/contents.html 2026-06-03T14:06:51.211Z https://bdef-book.com/index.html 2026-06-03T14:05:03.191Z https://bdef-book.com/errata.html 2026-06-03T13:48:28.185Z