Anyone reading about ZAX today will encounter the Abyss and a demon named Choronzon within a paragraph or two. Neither is Dee's.
The Abyss is a Kabbalistic idea: a gulf on the Tree of Life separating the three supernal sephiroth from the seven below, which the aspirant must cross and in crossing must surrender everything personal. The Golden Dawn taught it. Aleister Crowley brought it to the Enochian Aethyrs, and in doing so imposed a structure on the thirty that Dee's material does not contain.
Crowley worked the Aethyrs twice. In 1900, in Mexico, he began with the thirtieth and worked inward, stopping at the twenty-ninth because he judged his grade did not entitle him to go further. He resumed in 1909 in the Algerian desert in the company of the poet Victor Neuburg, and completed the sequence. The record was published as The Vision and the Voice, appearing in The Equinox in 1911. The working at ZAX, in which Crowley reported an encounter with Choronzon inside a protective circle while Neuburg recorded, is the most famous episode in modern Enochian practice and one of the most famous in modern occultism generally.
The point of provenance is straightforward. Crowley approached the Aethyrs having already decided that each group of three corresponded to a sephirah in sequence, and having already adopted the Golden Dawn's letter attributions. He then reported visions that matched those expectations closely. Benjamin Rowe, who worked the same material with deliberately minimal expectations, obtained results that did not match the Golden Dawn scheme at all and took this as evidence about how the material responds to the operator.
Read as a document of Thelemic practice, The Vision and the Voice is central. Read as evidence about what Dee received, it is a source about Crowley.