Reference for Nedarim 91:4
המודר הנאה מחבירו ויש לו מרחץ ובית הבד מושכרין בעיר אם יש לו בהן תפיסת יד אסור אין לו בהן תפיסת יד מותר
<b><i>GEMARA</i></b>. The scholars propounded: They differ when they interdicted themselves by vow. But what if each imposed a vow upon the other? Do we say, they differ [only] in the former case, but that in the latter the Rabbis agree with R. Eliezer b. Jacob, since they are involuntarily prohibited;<span class="x" onmousemove="('comment',' For if they voluntarily interdict themselves of all benefit, it may be maintained that each thereby renounces also his share, which is inseparable from his partner's. But when each forbids the other, it may be argued that neither can prohibit that which the other enjoys in his own right. ');"><sup>3</sup></span>