Complex sentence: Ethnographic literature most commonly uses "Blackfoot people", and most Blackfoot people use the singular Blackfoot, though the US and tribal governments officially use "Blackfeet" as in Blackfeet Indian Reservation and Blackfeet Nation as seen on official tribe website.
Split into simpler sentences: Ethnographic literature most commonly uses "Blackfoot people", and most Blackfoot people use the singular Blackfoot. The US and tribal governments officially use "Blackfeet", as in Blackfeet Indian Reservation and Blackfeet Nation, as seen on official tribe website.