Halim, Lukman, Savitri Sayogo, and Handaja Handaja. 1997. “Relationship Between Calcium Intake, Serum Ionized Calcium and Elevated Blood Pressure in Primigravida After 24 Weeks of Gestation”. Medical Journal of Indonesia 6 (4), 216-20. https://doi.org/10.13181/mji.v6i4.830.