Back issues of my article in Old Cardboard, which is the most comprehensive info on the set, are still available at
https://www.oldcardboard.com/subscriptions.asp
From the Old Cardboard M116 checklist page:
"For a detailed description of the Sporting Life set, see article by Tim Newcomb in Old Cardboard magazine (1910-12 M116 Sporting Life: A (Mostly) Pastel Treasure, Issue #18, Winter 2009, p. 14)."