Reference for Keritot 29:49
אמר רבה
Abaye raised an objection against Rabbah: [It has been taught:] R'Eliezer declares one culpable for derivatives<span class="x" onmousemove="('comment',' There are altogether thirty-nine principal acts of work prohibited on the Sabbath. Each of them is the head of a series of acts of work similar to it and derived from it - the derivatives. If a principal act has been performed together with some of its derivatives in one spell of unawareness, he is liable, according to R. Eliezer, for each act. From the fact that R. Eliezer did not go a step further in stating that even if the same principal act had been performed several times he is liable for each act, we derive that in the latter case he is only liable to one sacrifice.');"><sup>29</sup></span>