I had an argument with my colleague about the usage of the indefinite article in this sentence:
this system uses OAuth 2 as an authentication scheme, a documentation of the authentication service can be found here:
his argument was that the use of
a documentation is wrong because we're talking about a specific one here, and that it should be
My argument was that we mentioned the documentation for the first time here, and it should be indefinite.
Which one is correct? please provider a reference/evidence if possible.