Volatile constituents of the aerial parts of Ferulago subvelutina Rech. f., Ferulago stellata Boiss., leaves and flowers of Prangos ferulacea (L.) Lindle. and leaves of Ferula ovina (Boiss.) Boiss.: four Umbelliferae herbs from Iran - Taherkhani, M; Rustaiyan, A; Masoudi, S (Asian J Chem, 2012)