About: http://webisa.webdatacommons.org/23474013

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	It is the same trick than the one used in another question, i.e. to use the names that pgf-umlsd gives to the nodes from and to of each message, with a little calculation to adjust the position of the corners of the rectangle.
http://www.w3.org/ns/prov#wasQuotedFrom	stackexchange.com