Course in Draughts
To learn more about draughts, download the Course in Draughts books written by the Dutch master Tjalling Goedemoed.
Christiaan Piens has written several books that can be downloaded for free. The books contains hundreds of pages with analyses, exercises and more. The language of the books is dutch. They can be downloaded from http://www.damsport.be, under the Service / E-books menu.