• http://www.saber.ula.ve/handle/123456789/52474
• http://www.saber.ula.ve/handle/123456789/52475
• http://www.saber.ula.ve/handle/123456789/52476
• http://www.saber.ula.ve/handle/123456789/52477
• http://www.saber.ula.ve/handle/123456789/52478
• http://www.saber.ula.ve/handle/123456789/52479
• http://www.saber.ula.ve/handle/123456789/52481
• http://www.saber.ula.ve/handle/123456789/52482