1. The Middle School: The Natural Home;Beane;Educ. Leadersh.,1991
2. Education GPS—Spain—Student performance (PISA 2018)https://gpseducation.oecd.org/CountryProfile?primaryCountry=ESP&treshold=10&topic=PI
3. Informe Español. Estudio Internacional Sobre la Formación Inicial en Matemáticas de los Maestros. Análisis Secundario,2013
4. Develop your own philosophy;Anglin;New Teach. Advocate,1999
5. National Council of Teachers of Mathematicshttps://www.nctm.org/