• https://repositorio.upse.edu.ec/handle/46000/13658
• https://repositorio.upse.edu.ec/handle/46000/13657
• https://repositorio.upse.edu.ec/handle/46000/13659
• https://repositorio.upse.edu.ec/handle/46000/13660
• https://repositorio.upse.edu.ec/handle/46000/13661
• https://repositorio.upse.edu.ec/handle/46000/13662
• https://repositorio.upse.edu.ec/handle/46000/13663