Kalipa, Z., et al. “Factors Influencing Adherence to Folic Acid and Ferrous Sulphate Nutritional Intake Among Pregnant Teenagers in Buffalo City Municipality, South Africa”. Pakistan Journal of Nutrition, vol. 16, no. 7, June 2017, pp. 531–537, https://doi.org/10.3923/pjn.2017.531.537.