Medrano S., Krug P.J., Gosliner T.M., Biju Kumar A. & Valdés Á. (2018). Systematics of Polybranchia Pease, 1860 (Mollusca: Gastropoda: Sacoglossa) based on molecular and morphological data. Zoological Journal of the Linnean Society. , available online at http://10.1093/zoolinnean/zly050/5077298 5