Reference for Yevamot 242:5
ורבי מאיר מאי טעמא אמר רב כהנא כיפין על גב כיפין הוו ורבנן דשישא הוו ור"מ א"א דלא מסריך וניים פורתא
— Rather because he does not sleep. For R. Johanan stated: [A man who said]. 'I take an oath that I will not sleep for three days' is to be flogged<span class="x" onmousemove="('comment',' Malkoth (v. Glos.); for taking a false oath. It is impossible for a human being to live for three days without sleep. ');"><sup>16</sup></span> and he may sleep at once.<span class="x" onmousemove="('comment',' In three days' time, accordingly, a man who had fallen into a cistern would inevitably succumb to fatigue and the physical necessity for sleep, and would in the natural course of events be drowned. ');"><sup>17</sup></span> What then is R. Meir's reason?<span class="x" onmousemove="('comment',' If no one can withstand the necessity for sleep, why does not R. Meir, in the circumstances mentioned, admit the evidence? ');"><sup>18</sup></span> — R. Kahana replied: There were<span class="x" onmousemove="('comment',' In the cistern mentioned in our Mishnah. ');"><sup>19</sup></span>