"cell." Britannica School, Encyclopædia Britannica, 24 Apr. 2024. school.ebonline.com/levels/middle/article/cell/273572. Accessed 6 Sep. 2024.
"Anthony van Leeuwenhoek." Britannica School, Encyclopædia Britannica, 20 Aug. 2024. school.ebonline.com/levels/middle/article/Anthony-van-Leeuwenhoek/275421. Accessed 6 Sep. 2024.