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• https://en.wikipedia.org/wiki/Uncountable_set

• http://ed.ted.com/lessons/how-big-is-infinity#watch

• http://ed.ted.com/lessons/the-infinite-hotel-paradox-jeff-dekofsky

• https://en.wikipedia.org/wiki/Cantor_set

• https://en.wikipedia.org/wiki/Georg_Cantor's_first_set_theory_article

• https://atelieruldematematica.wordpress.com/2012/09/02/despre-infinitul-numarabil/

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