For Sphenoclea
Lammers. 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