This HTML5 document contains 4 embedded RDF statements represented using HTML+Microdata notation.

The embedded RDF content will be recognized by any processor of HTML5 Microdata.

PrefixNamespace IRI
isaphttp://webisa.webdatacommons.org/prov/
isahttp://webisa.webdatacommons.org/
rdfhttp://www.w3.org/1999/02/22-rdf-syntax-ns#
n5blogspot.
provhttp://www.w3.org/ns/prov#
xsdhhttp://www.w3.org/2001/XMLSchema#
Subject Item
isa:268832137
rdf:type
prov:Entity
prov:value
And if you view the relations as perfectly symmetric, so that it is arbitrary to define N as against S (which makes sense, because the relations themselves have been stripped of any content other than distinction), then this is nothing other than a naming convention for the three entities.
prov:wasQuotedFrom
n5:com
Subject Item
isap:433790838
prov:wasDerivedFrom
isa:268832137