The official Wikipedia rule is that all material must be verifiable from a reliable source. There is a whole lot of policy and debate behind that rule; for a s

The official Wikipedia rule is that all material must be verifiable from a reliable source. There is a whole lot of policy and debate behind that rule; for a start see https://en.wikipedia.org/wiki/Wikipedia:Verifiability https://en.wikipedia.org/wiki/Wikipedia:Verifiability and https://en.wikipedia.org/wiki/Wikipedia:Reliable_sources https://en.wikipedia.org/wiki/Wikipedia:Reliable_sources