David Glantz & Jonathan House's Stalingrad "trilogy" (really 5 volumes including companion material) is the granddaddy of all Stalingrad discussion. But, it's very long and somewhat pricey. There is a single-volume abridged version, but I have not read it yet so I can't speak to what the differences might be.

Beevor's Stalingrad: The Fateful Siege, 1942-1943 is quite accessible, but I find that in general Beevor's treatment of the Nazi-Soviet War falls back on some questionable tropes, such as German military prowess vs. uncaring Soviet commanders with hordes of men at their disposal. So, you'd have to take him with a grain of salt.

General Vasily Chuikov's Battle for Stalingrad is of course not a scholarly work but a memoir. However, despite the bias inherent in the fact that the author was one of the combat commanders in the battle - it's a damn good read. Just don't take it uncritically.

From the German perspective, although they are not in-depth looks at Stalingrad, the tail end of Rob Citino's Death of the Wehrmacht and the beginning of The Wehrmacht Retreats look at Stalingrad in the broader German strategic and mental context.