Reference for Rosh Hashanah 20:10
תניא רבי אליעזר אומר בתשרי נברא העולם בתשרי נולדו אבות בתשרי מתו אבות בפסח נולד יצחק בראש השנה נפקדה שרה רחל וחנה בראש השנה יצא יוסף מבית האסורין
Seeing that the month was only one day old and it is yet called 'month', we can conclude that one day in a month is reckoned as a month; and since one day in a month is reckoned as a month, thirty days in a year are reckoned as a year, a month being reckoned by its unit and a year by its unit. <br>(We infer from what has just been said that both [R'Meir and R'Eleazar] were of opinion that the world was created in Nisan).<span class="x" onmousemove="('comment',' Because both agree that 'the first day of the first month' in the text marks the beginning of another year. Rashi points out that both might equally well hold that the 'first month' here means Tishri, it being so called as first month to the creation and he therefore rejects this sentence. kkfn But v. Tosaf. s.v. .');"><sup>8</sup></span> It has been taught: R'Eliezer says: In Tishri the world was created; in Tishri the Patriarchs<span class="x" onmousemove="('comment',' Abraham and Jacob.');"><sup>9</sup></span> were born; in Tishri the Patriarchs died; on Passover Isaac was born; on New Year Sarah, Rachel and Hannah were visited;<span class="x" onmousemove="('comment',' I.e., remembered on high.');"><sup>10</sup></span> on New Year Joseph went forth from prison