Reference for Rosh Hashanah 19:3

פעמים שברביעית ועדיין אסורה משום ערלה ופעמי' שבחמישית ועדיין אסורה משום רבעי

There are occasions when fruit appears in the fourth year and it is still forbidden on account of uncircumcision', and there are occasions when fruit appears in the fifth year and it is still forbidden on account of 'fourth year'. Shall I say that that is not [in agreement with] R'Meir,<span class="x" onmousemove="('comment',' The view that thirty days are required to count as a year.');">⁴</span>

Jastrow