Osteoporosis Canada: Calcium - An Essential Element for Bone Health - http://www.osteoporosis.ca/english/About%20Osteoporosis/Nutrition/ Tells why we need calcium in our diets, gives daily calcium requirements for different age groups, talks about the effects of salt and caffeine on our calcium requirement, and gives the calcium content of some common foods.
Keep Kids Healthy: Calcium Requirements - http://www.keepkidshealthy.com/nutrition/calcium_requirements.html Article about the nutritional requirements and dietary sources for this mineral.
MedlinePlus: Calcium - http://www.nlm.nih.gov/medlineplus/calcium.html Lists links to many articles on calcium and our health from government and health agencies.