Barke, J. al., et Supplemental material: Orbitally forced Azolla blooms and Middle Eocene Arctic hydrology: Clues from palynology GSA Data Repository Item 2011141, Geology. File size: about 88 KB. Geoscience 2011-01-01
    https://gsapubs.figshare.com/articles/journal_contribution/Supplemental_material_Orbitally_forced_Azolla_blooms_and_Middle_Eocene_Arctic_hydrology_Clues_from_palynology/12527108
10.1130/2011141