id	author	title	date	pages	extension	mime	words	sentence	flesch	summary	cache	txt
cet-13151		cet-13151		6	.pdf	application/pdf	4498	175	53	The main obstacle to gaseous H2 delivery is its low volumetric density, which would lead to excessive dimensions of the storage and transport equipment. H2 liquefaction occurs at about 20 K and atmospheric pressure.	cache/cet-13151.pdf	txt/cet-13151.txt