One thread must exist on chesspublishing forum because I recorded one post from "Paddy" about the line 7.Qg4 Nf5 8.Bd3 h5 9.Qf4! quoting Moles 1975 book.
I have also:
- Hebert's analysis about Petrosian's games and 9.Qf4 Qh4 variation. (former world champion played it : Leonid Stein-Tigran Petrossian, 28th URSS championship 1961 and 22 years later

Tal-Petrossian)
- some lines analyzed by Psakhis with 9.Qf4 Nc6 10.Nf3!?: Bryson-Rozentalis,Cappelle La Grande 2003, Rytshagov-Raivio,Heart of Finland 1995, Kruppa-Rozentalis,Podolsk 1989,
- game: Pietzsch-Stolz,olympiades 1952 (Suetin)
Assessment in books look same as the one given by kgwm, "playable" for Black
For White I will advice the 8.Bd3 h5 9.Qf4 line
For Black I advice : 9...Qc7!? see forum and Inn2 post about Carlsen-Pelletier,Biel 2005 (and other Pelletier games: Short-Pelletier,Zurich 2001 and Volokitin-Pelletier,Blitz ACP 2004 )