18.Imdad A, Bhutta ZA. Effects of calcium supplementation during pregnancy on maternal, fetal and birth outcomes. Paediatr Perinat Epidemiol. 2012 Jul;26 Suppl 1:138-52. http://www.ncbi.nlm.nih.gov/pubmed/22742607
19.Hovdenak N, Haram K. Influence of mineral and vitamin supplements on pregnancy outcome. Eur J Obstet Gynecol Reprod Biol. 2012 Oct;164(2):127-32. http://www.ncbi.nlm.nih.gov/pubmed/22771225
20.Pfeifer M, Begerow B, Minne HW, Nachtigall D, Hansen C. Effects of a short-term vitamin D3 and calcium supplementation on blood pressure and parathyroid hormone levels in elderly women. J Clin Endocrinol Metab. 2001;86:1633–1637. http://www.ncbi.nlm.nih.gov/pubmed/11297596