In the Plot section, Mike de Wolf and Horace Hackett should be referred to by either their last name or first name. You refer to the former by his first name and the latter by his last name.
In the Plot section: Up there - God? Is this an em dash or en dash?
In the Genres section: Roland J. Green of the Chicago Sun-Times also described the work as a "classic", and wrote positively of Hubbard's novel Final Blackout. I don't think that Final Blackout is relevant here.
In the Reception section: "Typewriter in the Sky, which first appeared in Unknown in 1940. is widely considered to be one of his best works." You may have misquoted this because the period in the middle of the sentence seems odd.
In the Influence section: I bet if L. Ron Hubbard had written Purple Rose of Cairo they'd have given it a Hugo ... I mean, it is sort of a hip, updated version of Typewriter in the Sky. Is Purple Rose of Cairo and Typewriter in the Sky italicized in the corresponding reference?