Football coach (1871–1954) responsible for devising the double-wing formation, the “Pop Warner League” is named in his honor. Vintage ink signature, “Glenn Scobey Warner,” on a light blue 4.5 x 2.75 slip which is affixed to a 6.25 x 3.5 heavier stock sheet. In fine condition. Auction LOA Steve Grad/PSA/DNA and R&R COA.