Behmadi, Hossein, Saadati, Seyed Mahdi, Roshani, Mina, Mohammadi, Hasan, Razavi, Abbas, Ramezani, Marjan (2009). Sulfuric acid immobilized on silica: A versatile and reusable heterogeneous catalyst for the synthesis of phenanthrimidazole derivatives. *Journal of the Iranian Chemical Research*, 2(3), 183-187.