John Ruskin (1868). “Time and Tide, by Weare and Tyne. Twenty-five letters to a Working Man of Sunderland (Thomas Dixon) on the laws of work ... Second edition”, p.37
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
John Ruskin, Charles Eliot Norton, John Lewis Bradley, Ian Ousby (1987). “The Correspondence of John Ruskin and Charles Eliot Norton”, p.79, Cambridge University Press