“Astudy and Analysis of Geomagnetic Field By Using Model of International Geomagnetic Reference Field (IGRF- 2000)”. Ibn AL-Haitham Journal For Pure and Applied Sciences, vol. 19, no. 2, Nov. 2017, pp. 29-37, https://jih.uobaghdad.edu.iq/index.php/j/article/view/1566.