Manusmriti
अकामतस्तु राजन्यं विनिपात्य द्विजोत्तमः । वृषभैकसहस्रा गा दद्यात् सुचरितव्रतः ॥ १२७ ॥
But if a Brahmana unintentionally kills a Kshatriya, he shall give, in order to purify himself, one thousand cows and a bull;
english translation
akAmatastu rAjanyaM vinipAtya dvijottamaH । vRSabhaikasahasrA gA dadyAt sucaritavrataH ॥ 127 ॥
hk transliteration by Sanscript