CC Madhya-lila 24.151 - Panini's sutras 1.2.64
Sri Caitanya-caritamrta
CC Madhya-lila
CC Madhya 24.151, Translation and Purport:
“‘Of words having the same form and case termination, the last one is the only one retained. For example, the word "rāmāḥ" is used to stand for "rāmaś ca, rāmaś ca, rāmaś ca, etc."’
This is a quotation from Pāṇini's sūtras (1.2.64).