Yahya related to me from Malik from Yahya ibn Said from Said ibnal-Musayyab that 'Umar ibn al-Khattab decided about the woman who wasmarried by a man and the marriage had been consummated, that thebride-price was obligatory.
USC-MSA web (English) reference: Book 28, Hadith 12
Arabic reference: Book 28, Hadith 1105