I use the Big Book as the basic reference for what the AA programme is.
Over the years, all sorts of other ideas have helped alcoholics in AA. Sometimes, ideas come along that are not so helpful to alcoholics.
It is very simple to determine whether a particular phrase is in the Book. Any fool can do that, and trumpet that everything else 'ain't AA'.
It is trickier to work out whether an idea is contained in the Big Book, because that requires a bit of intelligence and a bit of critical thought.
A good example is sponsorship. The first few chapters do not mention sponsorship. Some people will not have sponsors or call themselves sponsors, therefore. However, the actions most people associate with sponsorship are indeed contained within the Book, specifically in Chapter Seven, and illustrated further in Chapter Eleven.
There is a value in determining whether particular words or phrases are in the Book, so thank you, anyone with the knowledge or time to determine that for us. That is all that has been achieved, however: it has not been demonstrated whether the idea the words or phrase represents are in the Book. That is a horse of a different colour!