Α) http://repository.edulll.gr/edulll/retrieve/3452/1014.pdf
Β) http://www.pmglp.org/01in/siondas_theoria.pdf
Γ) https://analogorama.wordpress.com/2011/10/24/%CE%B7-%CE%B8%CE%B5%CF%89%CF%81%CE%AF%CE%B1-%CF%84%CE%B7%CF%82-%CE%BC%CE%BF%CF%85%CF%83%CE%B9%CE%BA%CE%AE%CF%82/
Δ) http://www.pmglp.org/index.php/el/arxiki/diaxeirisi/30-2010-12-02-00-27-39/2010-12-02-00-29-14/17-mus-yliko?showall=1
Β) http://www.pmglp.org/01in/siondas_theoria.pdf
Γ) https://analogorama.wordpress.com/2011/10/24/%CE%B7-%CE%B8%CE%B5%CF%89%CF%81%CE%AF%CE%B1-%CF%84%CE%B7%CF%82-%CE%BC%CE%BF%CF%85%CF%83%CE%B9%CE%BA%CE%AE%CF%82/
Δ) http://www.pmglp.org/index.php/el/arxiki/diaxeirisi/30-2010-12-02-00-27-39/2010-12-02-00-29-14/17-mus-yliko?showall=1