How were these GPS points obtained?
Collected the information from several sources. For the Den Haagse Molen, this source was used: http://www.dewolffnederlandwindenergie.nl/bouw-windturbine-de-haagse-molen/

For the Duinvogel, these sources were used:
http://www.vogelwijkenergiek.nl/activiteiten/onze-windmolen/
http://www.vogelwijkenergiek.nl/de-duinvogel-moet-voortijdig-verdwijnen/

The information was combined into one table.