Welcome Marek! And you could not have made a better entrance here than with a Bontekoe track bike! Gerrit Bontekoe was a rather good track rider, and training partner of the even better Piet Moeskops, in the 1920's when there was a ban on road racing and track racing was very popular. He started his own bike shop in The Hague. His son was a good frame builder, your bike may be one of his. Like Italuminium says, the shop is still there, currently run by two grandsons. You could try contacting them through their website if you want to know more about your bike:
http://www.bontekoewielersport.nl
This is Gerrit:
