Some more...
Daily Telegraph, (2001)
https://www.telegraph.co.uk/finance/property/4814433/Inside-story-29-Wolverton-Street.htmlentertaining short article by Roger Wilkes
Yahoo!Groups, (2003)
https://archive.ph/20130105185113/http://dir.groups.yahoo.com/group/unsolvedbritishmurders/message/27Another entertaining article, from a Crime Compendium, in Wallace's favour
F. Tennyson Jesse, (1953), essay "Checkmate"
https://www.dropbox.com/s/og96f9012qelpni/CHECKMATE.pdf?dl=0Thinks Wallace guilty, on nothing more than a hunch. Bizarrely proposes that Wallace disposed of the murder weapon in the River Mersey. Anfield is three miles inland...
In A City Living, (2011) blogspot [illustrated with many photos]
https://inacityliving.blogspot.com/2012/11/the-wallace-murder-case.htmla neutral recitation of the case, in great detail
Robert F Hussey - Murderer Scot-Free (1972)
basically endorses and develops Goodman's theory [either Mr "Y", OR another, "Mr "Z", acting alone, who correspond to Marsden and Parry, respectively]
Hargrave Lee Adam - Murder Most Mysterious (1932) [chapter]
https://archive.org/details/murdermostmyster00adam/page/261/mode/1up?view=theaterWallace probably didn't do it; a commentary on the trial and appeal.
John Brophy - The Meaning of Murder (1966), [chapter] "The Liverpool Classic"
Wallace didn't do it.
John Rowland - The Wallace Case (1949)
Wallace was innocent
John Gannon - The Killing of Julia Wallace (2012)
Wallace, Parry and Marsden conspired to kill Julia. Wallace "blackmailed" the boys into killing her because he discovered they were shagging Julia. Aside from the silly theory, there is a lot of [over-]detailed research on just about every aspect of the case, although very disorganised.
Yseult Bridges - Two Studies in Crime (1959)
Wallace did it. Biased and error-strewn. Tries to compare Wallace with the murderer Courvoisier, a century earlier.
Ronald Bartle - The Telephone Murder (2018)
Wallace did it. The first edition was ludicrously error-strewn.
Mark Russell - Checkmate: The Wallace Murder Mystery (2021)
Wallace did it. Biased and hugely intemperate in making his case.
Richard Waterhouse - The Insurance Man (1994) [very short and self-published, I think]
Wallace and Parry did it together.
Winifred Duke - Six Trials (1934) [chapter]
Possibly thinks Wallace innocent (I'm not sure, it's a very difficult book to find)
F.J.P. Veale - The Wallace Case (1950) [another short pamphlet]
I don't know what Veale thinks. The work is essentially unobtainable.