S. Khakwani, S. Aslam, M. N. Shahi, A. M. Rolim Bernardino, and M. A. Khan, “Mass Spectrometry of Heterocyclic Compounds: Benzo[b]pyrazolo[3,4-b]-1,6-naphthyridines”, ajc, vol. 28, no. 11, pp. 2385–2387, Aug. 2016.