Nutritional rickets: deficiency of vitamin D, calcium, or both?Do you have any sources for this? I'd like to read about it.
Vitamin D deficiency among northern Native Peoples: a real or apparent problem?
The second article is about the "paradox" that people living at northern latitudes with the least sunlight exposure have comparatively low prevalence of Rickets. The highest incidence of Rickets is in the sunniest parts of the world like Africa and Middle East.