‏الصيام : Hadeeth No:2365 This hadith is narrated on the authority of 'Ubaidullah with the same chain of transmitters, and he said: If (the sky) is cloudy for you, then calculate thirty days (for the month of Ramadan)....

‏الإيمان : Hadeeth No:336 Abu Bakr b. Abi Shaiba narrated it on the same authorities....