Search is your friend. You state:

Ive seen a couple examples given, but I would like to educate myself on the matter a bit more so that I can effectively argue against stalin apologists.

As this has been discussed here before at some length by u/International_KB, u/Kochevnik81, u/Kieslowskifan (and by me), it would help if you could specify just what aspect of the extensive prior answers seems inadequate.

More can always be said-- but I think that in prior answers you have a pretty complete picture of where Furr [doesn't] stand in academic estime.

See:

How do historians view Grover Furr’s book “Bloodlies”, which argues that Timothy Snyder’s book “Bloodlands” lies about Stalin’s mass murders?

and

Is "Khrushchev Lied" by Grover Furr just a bunch of pseudohistory and revisionism?

and

Video of a college professor saying that he has not found "evidence of ONE crime committed by Stalin" is gaining steam on /r/videos**.**