Šivel, Miroslav, Miroslav Fišera, Bořivoj Klejdus, Stanislav Kráčmar, Vlastimil Kubáň, Jozef Golian, and Blanka Svobodová. “Lutein in Food Supplements Available on the Markets of the Viszegrad Countries”. Potravinarstvo Slovak Journal of Food Sciences 8, no. 1 (November 17, 2014): 261–266. Accessed April 17, 2024. https://potravinarstvo.com/journal1/index.php/potravinarstvo/article/view/387.