W3schools. (s.f.). HTML DOM Input Radio Object. Recuperado de http://www.w3schools.com/jsref/dom_obj_radio.asp

W3schools. (s.f.). HTML DOM className Property. Recuperado de http://www.w3schools.com/jsref/prop_html_classname.asp

W3schools. (s.f.). JavaScript RegExp Reference. Recuperado de http://www.w3schools.com/jsref/jsref_obj_regexp.asp