Abd al-Rahman bin Abi al-Zinad (may Allah have mercy on him) narrated from his father (Abu al-Zinad), who said: The jurists I met whose word was final, among them Sa'id bin al-Musayyab, Urwah bin al-Zubayr, al-Qasim bin Muhammad, Abu Bakr bin Abd al-Rahman, Kharijah bin Zayd bin Thabit, Ubaydullah bin Abdullah bin Utbah and Sulayman bin Yasar, along with other eminent elders besides them, used to say about a person who has a nosebleed that he should wash off the blood and need not perform ablution, and about a person who laughs in prayer that he should repeat the prayer and need not repeat his ablution.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 678