| Digital Library | Real Jardín Botánico CSIC | |
| Google Books | ||
| Index of Botanical Literature | Harvard University Herbaria |
| Johnstone, W.G., Croall, A.: The Nature-Printed British Sea-Weeds. Volume 1. (1868) | Kurt Stübers Online Library | |
| Linnaeus, C. von: Species plantarum. Vol. 2 | Bibliothèque Nationale de France | Info |
| Linnaeus, C. von: Systema vegetabilium | Info | |
| Wettstein, R. Handbuch der Systematischen Botanik. Ed. 3 | Kurt Stübers Online Library | Info |