Khakwani, S. et al. 2016. Mass Spectrometry of Pyrazolo[3,4-b]pyrido[2’,3’-b]-1,6-naphthyridines and Dipyrazolo[3,4-b];3’,4’-h]-1,6-naphthyridines. Asian Journal of Chemistry. 28, 12 (Sep. 2016), 2601–2604. DOI:https://doi.org/10.14233/ajchem.2016.19947.