I purchased my copy [$14.95] at the Vicksburg National Military Park in 1998.
It was published by "Ole Sow" Publications, 1998. 100 Walnut Circle, Vicksburg, MS 39180.
I would assume the Park bookstore would still have it. If not, check the Old Courthouse Museum in Vicksburg.
By the way, it does not cover "all the deaths." Mostly, it records known burials.
Originally some 3000 Confederates were buried in the Vicksburg City Cemetery in Soldiers Rest. Unfortunately, over the years, the original records were lost and the Cyprus markers disintegrated. Subsequently, approximately 2000 have been identified on records which have been found.
The remaining 1000 are unknown except for those of the 43rd Tennessee which I have had listed in Webster's work.