Will Rogers, Bryan B. Sterling, Frances N. Sterling (1993). “Will Rogers' World: America's Foremost Political Humorist Comments on the Twenties and Thirties--and Eighties and Nineties”, p.167, Rowman & Littlefield
John Ruskin (1875). “Proserpina: Studies of Wayside Flowers, While the Air was Yet Pure Among the Alps, and in the Scotland and England which My Father Knew”, p.186