This blog would not have been possible without the help of God and Juan Miguel Reyes Montes, Manuel Saiz-Pardo Lizaso, Maria del Carmen Mateo Alcalá, Alejandro Ruiz Carrasco, Francisco Marin and Manuel Martin Diego. Thank you with all my heart for their collaboration and my gratitude for all of them.
Thank you very much, to all my teachers for everything they taught me, to my family for their patience and my friends.
