For Hydroleaceae
Angiosperm Phylogeny Group IV. 2016. An update of the Angiosperm Phylogeny Group classification of the orders and families of flowering plants: APG IV. Bot. J. Linn. Soc. 2016. Google Scholar
Bittrich & Amaral. 2016. In Kadereit, J.W., and V. Bittrich. 2016. The families and genera of flowering plants. XIV. Flowering plants – Eudicots – Aquifoliales, Boraginales, Bruniales, Dipsacales, Escalloniales, Garryales, Paracryphiales, Solanales (except Convolvulaceae), Icacinaceae, Metteniusaceae, Vahliaceae. Springer, Berlin. 412 pp. Google Scholar
Davenport, L.J. 2023. Hydroleaceae. In Flora of North America Editorial Committee. 2023c. Flora of North America north of Mexico. Volume 14, Magnoliophyta: Gentianaceae to Hydroleaceae. Oxford Univ. Press, New York, NY. 505 pp. Google Scholar
Ferguson, D.M. 1998. Phylogenetic analysis and relationships in Hydrophyllaceae based on ndhF sequence data. Systematic Botany 23: 253-268. Google Scholar
Hilger, H.H., and N. Diane. 2003. A systematic analysis of Heliotropiaceae (Boraginales) based on trnL and ITS1 sequence data. Bot. Jahrb. Syst. 125: 19-51. Google Scholar