7. 1. S Casson - American Journal of Archaeology, 1931 – JSTOR
http://www.jstor.org/stable/498564?seq=1#page_scan_tab_contents
2. GA Bécquer, R Acquaroni, F González, D Benito – 1991
http://webs.ono.com/alisesprofesor/documentos/lecturas4/07.%20Cruz%20
del%20diablo.pdf
3. Montesory method: The nature of education
http://scindeks.ceon.rs/article.aspx?artid=1452-73671002373M
11. 1. Historia de una escalera, drama en tres actos
https://books.google.com/books?id=SuJNjgEACAAJ&dq=%22historia+de+un
a+escalera%22+inauthor:Buero+inauthor:Vallejo&hl=es&sa=X&ved=0ahUKE
wjqi42i-anJAhXIPhQKHfWMDqIQ6AEILzAC
2. La piel del tambor
https://books.google.com/books?isbn=8484506487
3. Mutation
https://books.google.es/books?id=1o9uBAAAQBAJ&pg=PT3&dq=mutation+in
author:Robin+inauthor:Cook&hl=es&sa=X&redir_esc=y#v=onepage&q=mutati
on%20inauthor%3ARobin%20inauthor%3ACook&f=false