id	keyword
ap-9664	prague
ap-9664	time
ap-9664	system
ap-9664	czech
ap-9664	service
ap-9664	postal
ap-9664	rieger
ap-9664	time service
ap-9664	clock
ap-9664	sirens
ap-9664	state
ap-9664	public
ap-9664	file
ap-9664	czechoslovakia
ap-9664	technical
ap-9664	box
ap-9664	ppts
ap-9664	construction
ap-9664	františek
ap-9664	air