Complex sentence: In 2006 Yépez Cortés published his first novel "Las sombras de la Casa Mitre", and in 2009 its sequel "El árbol de las brujas", which are part of a trilogy whose third book has not yet been published (as of 2013).
Split into simpler sentences: In 2006 Yépez Cortés published his first novel "Las sombras de la Casa Mitre", and in 2009 its sequel "El árbol de las brujas". These two books are part of a trilogy whose third book has not yet been published (as of 2013).