https://www.youtube.com/watch?v=0kICLG4Zg8s
https://en.wikipedia.org/wiki/Noam_Chomsky#Chomsky_hierarchy ,
https://en.wikipedia.org/wiki/Chomsky_hierarchy#The_hierarchy
http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=1056813 (1956) ,
http://www.diku.dk/hjemmesider/ansatte/henglein/papers/chomsky1959.pdf ,
http://www.sciencedirect.com/science/article/pii/S0019995859903626
https://en.wikipedia.org/wiki/Digital_physics#Digital_vs._informational_physics
https://en.wikipedia.org/wiki/Automata_theory#Classes_of_automata
