Reference for Nedarim 48:5

היכי דמי שבועות הבאי אילימא דאמר שבועה אם לא ראיתי בדרך הזה מידעם קאמר

<b><i>GEMARA</i></b>. It was taught: Vows of exaggeration are invalid, but oaths of such a nature are binding. How are such oaths possible? Shall we say that one said. 'I swear [so and so] if I have not seen etc.' — he said nothing!<span class="x" onmousemove="('comment',' He did not complete his sentence. ');">⁴</span>

Jastrow