<Ol> <Li> Cold Springs (2004) </Li> </Ol> <Li> Cold Springs (2004) </Li> <P> Published individually first, then as an anthology titled Demigods and Magicians in 2016 . </P> <Ol> <Li> The Son of Sobek (2013) </Li> <Li> The Staff of Serapis (2014) </Li> <Li> The Crown of Ptolemy (2015) </Li> </Ol>

How many books has rick riordan written in total