Work found, with species-group names introduced therein:
Smith, S. 1979.Littorina rudis var scotia and its adaptation to the extreme environment of Rockall (Mollusca: Gastropoda). Porcupine Newsletter 1 138-139. [Stated date: -- May 1979.] Littorina rudis var. scotia, see Littorina saxatilis (Olivi, 1792)