ENS, école normale supérieure du Burundi.
Research microscope.
Royal Microscopical Society, 1839-1889. Snowflake ×10; Blue fly ×5; Blood cells ×500; Microchip ×600.
F. Zernike. Nobel Price physics, 1953.
Antoni van Leeuwenhoek, 1632-1723. Cultural and social care.
Dutch Cancer Society.
VN-Universität – Forschung.
First-day cover bearing a stamp tied by a cancellation showing the date of the official first …