Direct nitration of five membered heterocycles - Katritzky, Alan R.; Scriven, Eric F.V.; Majumder, Suman; Akhmedova, Rena G.; Akhmedov, Novruz G.; Vakulenko, Anatoliy V. (ARKIVOC, 2005)
doi: 10.3998/ark.5550190.0006.320