http://metro.co.uk/2016/04/11/big-bang-theory-star-thinks-the-show-could-run-for-another-five-to-ten-years-5809203/

"We could all have walking sticks doing The Big Bang Theory Season 20,” he says. "I think realistically there’s less time left now than there was on the show before. Maybe it will go to 11, 12 or 13. I will do it as long as I can. But I think it is somewhere in that range."

http://www.cinemablend.com/television/Big-Bang-Theory-May-End-According-Kunal-Nayyar-141507.html

The Big Bang Theory just wrapped up its ninth season a few weeks ago. At the time, fans weren’t too concerned about the CBS comedy, as the sitcom had already been renewed for Season 10. However, while all the t’s have been crossed and the i's have been dotted for next season, there’s been some concern that Season 10 might be the last for The Big Bang Theory. Recently, series actor Kunal Nayyar added fuel to the fire when he spoke out about the possibility of the series ending after Season 10. Here’s what he had to say while speaking at MCM Comic-Con London. Look - next season, as it stands on our contract, could be the last season of Big Bang Theory. To be completely honest…I know people are