Shia traditional reports on the topic that Imams are twelve in number

H 107 - Muhammad bin Abdullah bin Ja’far Himyari has narrated from his father from Ahmad bin Hilal Abratai from Ibn Abi Umair from Saeed bin Ghazwan from Abu Basir from Imam Ja’far Sadiq عليه السلام that he said: “Surely Allah chose the prophets from the people and chose the messengers from the prophets and chose me from the messengers and chose Ali عليه السلام from me. He granted him (Ali) superiority over all the successors. From Ali عليه السلام He chose Hasan عليه السلام and Husain عليه السلام and from Husain عليه السلام, He chose the successors from his descendants. The ninth of them is their Qaim (a.t.f.s.) and he is their apparent and their concealed.”