Ccolque Taipe, Felipe Clímaco. “Characterization of Relative Projectives and Relative Injectives”. Selecciones Matemáticas 7, no. 02 (December 25, 2020): 276-288. Accessed December 26, 2024. https://revistas.unitru.edu.pe/index.php/SSMM/article/view/3081.