• http://repositorio.certus.edu.pe/handle/certus/2
• http://repositorio.certus.edu.pe/handle/certus/9
• http://repositorio.certus.edu.pe/handle/certus/1
• http://repositorio.certus.edu.pe/handle/certus/6
• http://repositorio.certus.edu.pe/handle/certus/10
• http://repositorio.certus.edu.pe/handle/certus/11
• http://repositorio.certus.edu.pe/handle/certus/12