Reference for Menachot 154:5
נראה למי דומה דנין תרומה שאין אחריה תרומה מתרומה שאין אחריה תרומה ואל יוכיח בכורים שיש אחריהן תרומה
I can, however, infer it by the following argument: it is written here 'terumah', and it is written there in connection with the terumah of the tithe 'terumah';<span class="x" onmousemove="('comment',' Num. XVIII, 26. The Levites were to offer a tenth part of the tithe which they had received from the people to the priest.');"><sup>6</sup></span> as there it is on part in ten, so here it is one part in ten. Or perhaps argue this way: it is written here 'terumah', and it is written there in connection with the first-fruits 'terumah';<span class="x" onmousemove="('comment',' Cf. Deut. XII, 17: 'And the terumah of thy hand', which expression, according to Rabbinic interpretation, refers to the first-fruits. There was no prescribed measure for the first-fruits, v. Pe'ah I, 1.');"><sup>7</sup></span>