Reference for Pesachim 76:8

אמר שמואל בר רב יצחק רביעית היא ומתחלקת היא לכמה חלות

It was taught in accordance with R'Joseph: You might think that a man can discharge his obligation with the loaves of the thanksoffering and the wafers of a nazirite; therefore it is said, 'seven days ye shall eat unleavened bread', implying, unleavened bread which may be eaten seven days.

Jastrow