About: http://webisa.webdatacommons.org/82307938

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	Solitary black holes are very difficult to observe, but X-ray binary systems, such as M33 X-7, make black holes visible to us, said Francesca Valsecchi, a doctoral student in Kalogera's research group and lead author of the paper.
http://www.w3.org/ns/prov#wasQuotedFrom	eurekalert.org