Reported speech

http://www.perfect-english-grammar.com/reported-speech.html

https://www.englishclub.com/grammar/reported-speech.htm

http://www.englisch-hilfen.de/en/grammar/reported.htm

http://www.ego4u.com/en/cram-up/grammar/reported-speech

http://learnenglish.britishcouncil.org/en/grammar-reference/reported-speech-1