Sunan At-Tirmidhi
Hadith #623
Mu'adh bin Jabal narrated:""The Prophet sent me to Yemen and ordered me to collect a Tabi or a Tabi'ah on every thirty cows, a Musinnah on every forty, a Dinar for every Halim, or its equivalent of Ma'afir.""Abu Eisa said: This Hadith is Hasan. Some of them reported this Hadith from Sufyan, from Al-A'mash, from Abu Wa'il, from Masruq: ""The Prophet sent Mu'adh to Yemen and ordered him to take..."" and this is more authentic