Yahya related to me from Malik from Ibn Shihab from Urwa ibn az-Zubayr that Khawla ibn Hakim came to Umar ibn al-Khattab and said,''Rabia ibn Umayya made a temporary marriage with a woman and she ispregnant by him.'' Umar ibn al-Khattab went out in dismay dragging hiscloak, saying, "This temporary marriage, had I come across it, I wouldhave ordered stoning and done away with it! "
USC-MSA web (English) reference: Book 28, Hadith 42
Arabic reference: Book 28, Hadith 1137