A green protocol for synthesis of pyran annulated hetrocyclic systems using Na2SO4 as an efficient catalyst Malek Taher Maghsoodlou, Amin Masoumnia, Mir Rasul Mousavi, Nourollah Hazeri, Jasem Aboonajmi, Sayyed Mostafa Habibi-Khorasani, Shiva Kiaee, Requires Subscription PDF Requires Subscription HTML downloads: 156 views: 12