Nielsen, Lars Henrik, Flemming Larsen, and Nils Frandsen. 1989. “Upper Triassic-Lower Jurassic Tidal Deposits of the Gassum Formation on Sjælland, Denmark”. Danmarks Geologiske Undersøgelse Serie A 23 (October). Copenhagen, Denmark:1-30. https://doi.org/10.34194/seriea.v23.7043.