Yahya related to me from Malik, from Abd ar-Rahman ibn Harmalaal-Aslami, that somebody asked Said ibn al-Musayyab, "Can I do umrabefore I do hajj?", and Said said, "Yes, the Messenger of Allah, mayAllah bless him and grant him peace, did umra before doing hajj." (TR)
USC-MSA web (English) reference: Book 20, Hadith 58 (TR)
Arabic reference (TR): Book 20, Hadith 763 (TR)