Soleymane Kone, et al. “Cooperativity of Three Fragments : Protonated or Methylated Makaluvamine, Water Molecule and Glutamic Acid Molecule in Twelve Complexes and Their Stabilities. A Study Performed at B3LYP 6-31+G(D,P) Level”. Global Journal of Science Frontier Research, vol. 20, no. B1, Jan. 2020, pp. 1-10, https://journalofscience.org/index.php/GJSFR/article/view/2601.