About: http://webisa.webdatacommons.org/408335731

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	I do not see why they could not be writable in today's world, but I bet there was a good reason - once upon a time. :) While I didn't have the time to implement a solution myself, I did have an idea for what to do.
http://www.w3.org/ns/prov#wasQuotedFrom	dlaa.me