Rabbi Elazar, son of Rabbi Shimon, a) [The Rambam wrote that he is mentioned only in Chapter 4 of Tractate Temurah, Mishnah 4, and is mentioned again in Mishnah 4 of Tractate Beitzah, and in Nega'im, Chapter 12, Mishnah 3. In Chulin (according to the version of Rabbi Aharon), in Bekhorot (according to the version of Rabbi Avraham), the acronym for Rabbi Shimon is explained by Rashi that there are many Mishnas and Beraitot that Rabbi Shimon ben Gamliel said, and the Tana'im are accustomed to arrange them in the Mishnah in a general language (see Rabbi Yossi, son of Rabbi Yehudah)]:
Seder_HaDorot,_Tanaim_and_Amoraim.523:1