Reference for Eruvin 104:3
ר"מ אומר כל שיכול לערב כו': הא תנינא חדא זימנא ספק ר"מ ורבי יהודה אומרים הרי זה חמר גמל
R'MEIR RULED: WHOSOEVER IS ABLE TO PREPARE AN 'ERUB etc. Have we not already learnt this<span class="x" onmousemove="('comment',' That where an uncertainty exists as to which place had bee acquired as his Sabbath base, the man concerned is, in the opinion of R. Meir, in the position of an ass-driver and a camel-driver.');"><sup>5</sup></span> once: If this is doubtful, the man, said R'Meir and R'Judah, [is in the position of both] an ass-driver and a camel-driver?<span class="x" onmousemove="('comment',' Mishnah, supra 35a q.v. notes, from which it is evident that on account of an uncertainty the man, in the view of R. Meir, is to be placed in the position of an ass-driver and a camel-driver. Is not then the ruling in our Mishnah, which could have been deduced From the Mishnah, superfluous?');"><sup>6</sup></span>