Belgium and Luxembourg can be purchased via the Netherlands link above. 
Germany please visit – direct link to the book here

All other International orders (excluding the USA) the link above will re-direct to the Dutch answer to Amazon. This is to give you the cheapest possible shipping rate available for international orders. 
If you prefer to order direct from the author on this site it's possible but shipping is at higher cost. Please chose 'within the USA' and there are international shipping options available. 

Apologies for the clunky shipping options. I'm working on better options for international orders!