Bits and pieces put together by me, basically because I was researching a small wargames campaign based on the fighting above the Volga in late 1919. It turns out to have been a much larger scale operation than I thought.
Bits and pieces of the Soviet XI Army, which were the main forces in the lower Volga.
A couple of orders of battle for the White forces in the Volga area. The campaign towards Astrakhan' started in mid-1919 with a drive by General Dratsenko up the Caspian coast with the Astrakhan Forces Group, which later merged into the Forces of the North Caucasus under General Erdeli. Meanwhile Baron Wrangel pressed on towards Tsaritsyn, and after he had taken that he attacked down the Volga.
The Caucasian Army in October 1919 and, briefly, the Trans-Volga and Lower Volga Detachments.
The Forces of the North Caucasus in October 1919 and, briefly, the Astrakhan Forces Group.
Here are a couple of maps of the Tsaritsyn to Astrakhan stretch of the Volga for late 1919, the first from the "Encyclopedia of Civil War and Intervention in the USSR" and the second from "Combats of the XI Army from the Northern Caucasus to the Lower Volga: 1918 - 1920" by V. T. Sukhorukov.
I drew up a schematic map for my proposed campaign, which is basically correct except I "fixed" a few things to make them simpler to organise.
I then drew up maps of all the towns in the middle of the map so that any battles could be fought over. (The ones on the edges I decided could wait until they were needed