Musnad Abu Ya'la al-Mawsili 110:279

Zuhayr narrated to us, Yahya ibn Abi Bukayr narrated to us, Isra'il narrated to us, from Abdullah ibn Muslim, from Sa'id ibn Jubayr, from Ibn Abbas, who said: The Messenger of Allah (may Allah bless him and grant him peace) used to kiss the Yemeni Corner and place his cheek upon it.