Bams en Bine in Madurodam

From the year :	1956      Publisher :  ???
Author(s) :	Knud Bavngaard
ISBN-number :	none
Remark :	Translated from Danisch by Bets Bonde Jensen-Elze
Contents :	The twin bears Bams and Bine get an invitation to come to Madurodam but this is in the Netherlands. How will they get there? Yes, by balloon of course.