Here are two good links off the top of my head:

http://henrygeorge.org/bob/understanding-economics-site-map/
https://en.wikipedia.org/wiki/Land_value_tax

The best book on the subject is Henry George's Progress and Poverty. Here is a link to a PDF version:

https://mises.org/sites/default/files/Progress%20and%20Poverty_3.pdf