Imam Malik (may Allah have mercy on him) said that Sulayman bin Yasar (may Allah have mercy on him) and Abu Salamah bin Abd al-Rahman (may Allah have mercy on him) were both asked: Is judgement given by an oath and a witness? They said: Yes.
(b) Muhammad bin Sirin (may Allah have mercy on him) said that Qadi Shurayh (may Allah have mercy on him) judged by an oath and a witness.
(c) Ibn Sirin (may Allah have mercy on him) said that Abdullah bin Utbah bin Mas'ud (may Allah have mercy on him) judged by an oath and a witness.
(d) Hushaym (may Allah have mercy on him) narrates from Husayn (may Allah have mercy on him): I took my dispute to Abdullah bin Utbah (may Allah have mercy on him), and he judged by an oath and a witness.
(e) Abu Mijlaz (may Allah have mercy on him) said: Zurarah bin Awfa (may Allah have mercy on him) gave judgement, and he judged on my testimony alone.
(f) It is narrated from Abu Qays and Abu Ishaq that Qadi Shurayh (may Allah have mercy on him) accepted the testimony of each of them alone.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الشهادات / 20683