Jungert Alexandra, Spinneker Andre, Nagel Anja, and Neuhäuser-Berthold Monika. “Dietary Intake and Main Food Sources of Vitamin D As a Function of Age, Sex, Vitamin D Status, Body Composition and Income in an Elderly German Cohort”. Food & Nutrition Research00 (September 17, 2014). Accessed April 24, 2024. https://foodandnutritionresearch.net/index.php/fnr/article/view/662.