Letter to Shelley, August 1820, in H. E. Rollins (ed.) 'The Letters of John Keats' (1958) vol. 2, p. 323; echoing Edmund Spenser 'The Faerie Queen' (1596) bk. 2, canto 7, st. 28, l. 5: 'And with rich metal loaded every rift'
John Keats (2015). “John Keats - The Man Behind The Lyrics: Life, letters, and literary remains: Complete Letters and Two Extensive Biographies of one of the most beloved English Romantic poets”, p.709, e-artnow