Zubair, Arif, and Syed Ikramuddin Ali. 2002. “THE VARIATION OF CALCIUM, MAGNESIUM, SODIUM, POTASSIUM AND BICARBO­ NATE CONCENTRATION, PH AND CONDUCTIVITY IN GROUNDWATER OF KARACHI REGION”. Biological Sciences - PJSIR 45 (3):151-56. https://v2.pjsir.org/index.php/biological-sciences/article/view/1775.