Selim, N.M. et al. 2013. Synthesis of some heterocyclic compounds based on (2, 3-dioxo-2, 3-dihydro-1H-indol-1-yl) acetyl acetic acid derivatives. International Journal of Basic and Applied Sciences. 2, 2 (Apr. 2013), 153–159. DOI:https://doi.org/10.14419/ijbas.v2i2.721.