Coup Marks is an Artist Cooperative on the Flathead Reservation in Montana, founded in 1982, Founding members are: Larraine Big Crane, Michael Big Crane, Dwithy Billedeaux, J. E. Matt, Sylvia Matt and Ruth Silverthorne with advice from Jaune Quick-to-See Smith. Confer Lester, Patrick D, The Biographical Directory of Native American Painters, 1995, Tulsa, Oklahoma : SIR Publications, p.126.