Besides 30 EC core courses, students must select 15 EC of specialization courses out of a list of more than 30 courses. You can find them here (under downloads).
The specialization courses have to be discussed with your mentor (assistant, associate or full professor from your specialization) and approved by the Examination Committee. Most of these courses are 5 EC, some are 2.5 EC.
More information about the specialization courses can be found on Osiris course catalogue.