Aedo, C. 2023: A Monograph of the genus Geranium L. (Geraniaceae). Consejo Superior de Investigaciones Científicas (CSIC), Madrid.
Heenan, P.B.; Rogers, G.M. 2021: Recognition of Geranium cruentum sp. nov. (Geraniaceae) resolves a taxonomic conundrum in New Zealand cranesbills. New Zealand Journal of Botany 59(3): 397–408.