HTML Reference¹
HTML Unicode (UTF-8) Reference²
HTML5 semantische structuren³
CSS Reference⁴
Overzicht css selectors⁵
Bootstrap⁶

Links

[1]: http://www.w3schools.com/tags/
[2]: https://www.w3schools.com/charsets/ref_html_utf8.asp
[3]: http://www.w3schools.com/html/html5_semantic_elements.asp
[4]: http://www.w3schools.com/cssref/default.asp
[5]: http://www.w3schools.com/cssref/css_selectors.asp
[6]: https://getbootstrap.com/docs/5.3/getting-started/introduction/