[16] Therein, what is internal perception (saññā ajjhattā)? That perception which, of these or those beings, is internal (ajjhattaṃ), personal (paccattaṃ), one's own (niyakā), individual (pāṭipuggalikā), clung-to (upādinnā): perception born of eye-contact (cakkhusamphassajā saññā) … perception born of mind-contact (manosamphassajā saññā) — this is called internal perception.
Therein, what is external perception (saññā bahiddhā)? That perception which, of these or those other beings, other persons, is internal, personal, one's own, individual, clung-to: perception born of eye-contact … perception born of mind-contact — this is called external perception.
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.