id	author	title	date	pages	extension	mime	words	sentence	flesch	summary	cache	txt
ap-9664	Hrtus, Martin Dominik	Prague postal time service: clock and sirens – improbable connection	2024	11	.pdf	application/pdf	9481	609	59	Keywords: History of technology, Prague Postal Time Service, Czechoslovakia, 1930s, synchronised clocks, anti-aircraft sirens, civil defence, František Rieger, Prague. Licensed under a CC-BY 4.0 licence Published by the Czech Technical University in Prague PRAGUE POSTAL TIME SERVICE:	cache/ap-9664.pdf	txt/ap-9664.txt