Bustamante-Sánchez, Marcia, et al. “Thiourea Derivatives As Receptors in Pb(II) Sensors: Theoretical and Experimental Description”. Revista Cubana De Química, vol. 33, no. 2, Apr. 2021, pp. 91-112, https://cubanaquimica.uo.edu.cu/index.php/cq/article/view/5178.