Musannaf Ibn Abi Shayba 23:217

Ibn Fudayl narrated to us, from Abu Sinan, from Abdullah ibn Shaddad, that he heard some people mentioning a dream while he was praying. When he finished, he asked them about it, but they concealed it from him. He said, "As for it, the interpretation of the dream of Yusuf came after forty," meaning years.