G. W. Brown 
Brown G. W., 1978, Preliminary report on an articulated specimen of Pteranodon (Nyctosaurus) gracilis. Nebr. Akad. Sci. aff. Socs Proc. 88, 39.
Brown G. W., 1986, Reassessment of Nyctosaurus: new wings for an old pterosaur. Proc. Nebr. Acad. Sci. p. 47.