@article{YamadaGradstein1991,
  author    = {Kohsaku Yamada and Stephan Robbert Gradstein},
  title     = {The genus Radula (Hepaticae) in the Galapagos Islands},
  journal   = {Tropical bryology},
  number    = {4},
  pages     = {63 -- 68},
  year      = {1991},
}