<http://ns.inria.fr/covid19/PMC7167062#title>	<http://purl.org/dc/terms/subject>	"Economics of transport and utility industries" .
<http://ns.inria.fr/covid19/PMC7167062#title>	<http://purl.org/dc/terms/subject>	"Airlines" .
<http://ns.inria.fr/covid19/PMC7167062#title>	<http://purl.org/dc/terms/subject>	"Aviation industry" .