The Rambam, if I recall correctly, is in the introduction to the second chelek of Moreh Nevuchim. The Yerushalmi is at the beginning of Horayos. I’m not sure where the Riva is – I saw it quoted in a few places, but it didn’t say exactly where it’s from. It does say it’s in response to Rashi’s quoting the Sifrei, so maybe look on that posuk?
The Ramban is on Devarim 17, and while he does say we need to listen even if it’s wrong, he qualifies that this is only for the Sanhedrin.