[1] JavaScript SDK - Facebook開発者 ( 版) http://developers.facebook.com/docs/reference/javascript/
[2] FB.XFBML.parse() ( 版) https://developers.facebook.com/docs/reference/javascript/FB.XFBML.parse
[3] Facebookボタンの設置・OGPの設定方法 | cly7796.net, https://cly7796.net/blog/other/how-to-install-the-facebook-button/
[4] Facebookのfb:like要素を設置したページを(X)HTML validにする方法: 小粋空間, , https://www.koikikukan.com/archives/2011/06/03-015555.php
[5] Markup | 2019 | The Web Almanac by HTTP Archive, https://almanac.httparchive.org/en/2019/markup