GOHAR, G. A., and M. E. MAHMOUD. “?MASS SPECTRAL STUDIES ON SOME NITROBENZYLIDENE THIOA CETAL DERIVATIVES”. Biological Sciences - PJSIR, vol. 40, no. 5-12, Oct. 1997, pp. 1-7, https://v2.pjsir.org/index.php/biological-sciences/article/view/2336.