Sayyiduna Ali (may Allah be pleased with him) narrates from the Prophet (peace and blessings be upon him) that he judged by an oath along with a single witness.
Ali bin al-Husayn bin Ali bin Abi Talib, the grandfather of Ja'far bin Muhammad, even though he did not meet Ali (may Allah be pleased with him), is closer to a connected chain than the narration of Muhammad bin Ali from Ali (may Allah be pleased with him); and others besides Ja'far bin Muhammad have narrated it from Muhammad bin Ali al-Baqir as mursal.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الشهادات / 20659