Ahmad, Manzoor, et al. “INTRACRANIAL HAEMANGIOPERICYTOMA: A VERY RARE ENTITY HAVING A HIGH MALIGNANT METASTATIC POTENTIAL”. Journal of Ayub Medical College Abbottabad, vol. 21, no. 4, Dec. 2009, pp. 174-6, https://jamc.ayubmed.edu.pk/index.php/jamc/article/view/3172.