Sunan At-Tirmidhi
Hadith #113
Aishah narrated:""The Prophet was asked about a man who finds wetness and he does not remember having a wet dream. So he said: 'He is to perform Ghusl. And (he was asked) about a man who had a wet dream but does not find any wetness, so he said: 'No Ghusl is required of him.' Umm Salamah said: 'O Messenger of Allah! Is the woman required to perform Ghusl if she sees that?' He replied: 'Yes. Indeed women are the partners of men