Fyscope 2 Piece Wide Angle Huygens 5x/10x/12.5x16x Eyepieces 23.2mm Dia For Biological Microscope Eyepieces Lens - Microscopes - AliExpress
History of Science and Medicine Library: A Catalogue of the Manuscripts of Christiaan Huygens Including a Concordance with His Oeuvres Complètes (Series #35) (Hardcover) - Walmart.com