* Stace, C. A.. ''New Flora of the British Isles''. Fourth. Middlewood Green, Suffolk, U.K.: C & M Floristics, 2019. ISBN 978-1-5272-2630-2 | * Stace, C. A.. ''New Flora of the British Isles''. Fourth. Middlewood Green, Suffolk, U.K.: C & M Floristics, 2019. ISBN 978-1-5272-2630-2 |