Ibn 'Abbas (RAA) narrated, "The Messenger of Allah (ﷺ) slaughtered a ram for both al-Hasan and al-Husain (at their birth).' Related by Abu Dawud, Ibn Khuzaimah, Ibn al-Garud and 'Abdul Haqq graded it as Sahih. (DE)
English reference (DE): Book 12, Hadith 1396 (DE)
Arabic reference (DE): Book 12, Hadith 1355 (DE)