Sunni sources: Ibn Zubair born from Mutah

Imam of Ahl as-Sunnah al-Raghib al-Isfahani reported in al-Maudhoorath Volume 2 page 96:
"Ibn Zubair denounced Ibn Abbas for his opinion on Mut'ah. Thus Ibn Abbas told him: "Go and ask your mother what she did with your father." When Ibn Zubair asked her, she said: "By God, I did not conceive you except through Mut'ah".


Imam of Ahl as-Sunnah Imam Abu Ja'far Ahmad At-Tahaawee, in his Sharh Ma'ani al Asar Volume 2 page 14, Chapter on Mut'ah, a hadeeth of Saeed bin Jabeer who discusses a conversation between Ibn 'Abbas and Abdullah ibn Zubayr:
"I heard Abdullah ibn Zubayr reading a sermon wherein he condemned Abdullah ibn Abbas for believing in the permissibility of Mut'ah. Ibn Abbas said "You should ask your mother about this if you are truthful. His mother said "Ibn 'Abbas spoke the truth Mut'ah did indeed exist'. Ibn Abbas then said; "If you like I can cite the names of the men from Quraysh who were born from Mut'ah."