M. Abass, E. A. Mohamed, M. M. Ismail, and A. S. Mayas, “Substituted Quinolinones. Part 16. Preparation and reactions of 3-(4-hydroxy-1-methyl-2-oxo-1,2-dihydroquinolin-3-yl)-3-oxopropanoic acid”, Eur. J. Chem., vol. 2, no. 3, pp. 378–387, Sep. 2011.