Makvandi, Marzieh, et al. “Silica-Bonded N-Propyltriethylene-Tetramine As a Recyclable Solid Base Catalyst for the Synthesis of 2-Amino-5-Oxo-5,6,7,8-Tetrahydro-4H-Chromenes”. Iranian Journal of Catalysis, vol. 3, no. 4, Feb. 2024, https://oiccpress.com/ijc/article/view/3777.