Reith's knapsack is mentioned on a June 3, 2003 post at the History-Sites.com "Arms and Equipment" message board.
http://history-sites.com/cgi-bin/bbs53x/cwaemb/webbbs_config.pl
One of the posts mentions "Richmond Volunteers 1861 - 1865" by Louis H. Manarin and Lee A. Wallace Jr.
http://www.worldcat.org/oclc/1342692&tab=holdings?loc=Richmond+VA