Erasmus Darwin (1825). “The Botanic Garden: A Poem, in Two Parts ... The Economy of Vegetation, and The Loves of the Plants. With Philosophical Notes”, p.7
Erasmus Darwin (1800). “Phytologia; Or, The Philosophy of Agriculture and Gardening: With the Theory of Draining Morasses, and with an Improved Construction of the Drill Plough”, p.556