Ray, John, and Francis Willughby. 1673. Observations topographical, moral, & physiological made in a journey through part of the low-countries, Germany, Italy, and France: with a catalogue of plants not native of England, found spontaneously growing in those parts, and their virtues. London: Printed for John Martyn. Online: https://archive.org/details/observationstopo00rayj/page/n8
