20. Compulsory License
(1) If no agreement is reached on the conclusion of a license contract, the Office may grant a compulsory license:
(a) if the owner of the patent does not work his patent at all or works it insufficiently and cannot give legitimate reasons for his failure to act; a compulsory license may not be granted prior to the expiration of four years as from the filing date of the patent application or three years as from the date of grant of the patent, whichever period expires last;
(b) If an important public interest is endangered.
(2) The grant of a compulsory license shall not affect the right of the owner to obtain compensation in respect of the value of the license.