Laxmi Aheer, A R Kalla, Savita Bansal, Pawan Kumar, and Kishore Khatri, “The correlation of Ki-67 (MIB-1) proliferation index and progesterone receptor status with histological grade of meningioma: An observational study”, Int. J. Heal. Clin. Res., vol. 4, no. 20, pp. 341–344, Nov. 2021.