Musnad Ahmad 27:566

Muhammad ibn Ja'far and Hajjaj narrated to us, they said: Shu'bah narrated to us, from Muharib ibn Dithar, I heard Ibn Umar saying: "The Messenger of Allah, may Allah bless him and grant him peace, forbade the *duba* (gourd), the *hantam* (green glazed jar), and the *muzaffat* (pitch-coated vessel)." Shu'bah said: I heard him [say it] more than once. Hajjaj said: And he said: I am in doubt regarding the *naqir* (hollowed-out log). Hajjaj said: In his hadith, several times.