The Volkssturm fought both the Western and Eastern Allies.
Good books? Anything by Tony le Tissier e.g. "With our Backs to Berlin", "Death was Our Companion" are very worthwhile. Helmut Altner's "Berlin Dance of Death" is a good read about a Luftwaffe conscript and there are many descriptions of Volkssturm and other ad hoc groupings. David K Yelton's "Hitler's Volkssturm" is very well researched. Anthony Read and David Fisher "The Fall of Berlin" has lots of first hand accounts from 1933 - 1945.
However, "reliability" is a judgement you will have to make for yourself bearing in mind while you read that the surviving Germans tried to distance themselves from the Nazi Party etc.
Hi Alan Pegasus do a set of Germans in Berlin that is mostly civilian types etc ,you can see a review on www,plasticsoldierreview.com (sorry couldn't get the link to work) under Pegasus
BTW Alan I have sent you a PM & an e-mail. cheers John