Sahih Bukhari 1906

Narrated `Abdullah bin `Umar: Allah's Apostle said, The month (can be) 29 nights (i.e. days), and do not fast till you see the moon, and if the sky is overcast, then complete Sha'ban as thirty days. ..

Narrated Ibn `Umar: The Prophet said, The month is like this and this, (at the same time he showed the fingers of both his hands thrice) and left out one thumb on the third time. ..

Narrated Abu Huraira: The Prophet or Abul-Qasim said, Start fasting on seeing the crescent (of Ramadan), and give up fasting on seeing the crescent (of Shawwal), and if the sky is overcast (and you cannot see it), complete thirty days of Sha'ban. ..

Narrated Um Salama: The Prophet vowed to keep aloof from his wives for a period of one month, and after the completion of 29 days he went either in the morning or in the afternoon to his wives. Someone said to him You vowed that you would not go..

Narrated Anas: Allah's Apostle vowed to keep aloof from his wives for one month, and he had dislocation of his leg. So, he stayed in a Mashruba for 29 nights and then came down. Some people said, O Allah's Apostle! You vowed to stay aloof for one..

Narrated Abu Bakra: The Prophet said, The two months of `Id i.e. Ramadan and Dhul-Hijja, do not decrease (in superiority). ..