Quote by Sir Arthur Conan Doyle

Gregory: "Is there any other point to which you would wish to draw my attention?"
Holmes: "To the curious incident of the dog in the night-time."
Gregory: "The dog did nothing in the night-time."
Holmes: "That was the curious incident."

Please suggest source details if you know: book, page, year, online article address (url), correction (different author...), etc.. Thanks.