Falayh bin Suliaman فليح بن سليمان · The Book of Purification and its Sunnah

"The Prophet was asked about doubts (concerning ablution) during prayer. He said: 'he should not leave until he hears a sound or detects an odor.'"

"I was a servant of the Prophet, and Hasan and Husain was brought to him and (the infant) urinated on his chest. They wanted to wash it, but the Messenger of Allah said: 'Sprinkle water on it, for the urine of a girl should be washed, but the urine of a boy should be sprinkled over with water.'"

The Messenger of Allah said: "The urine of a boy should be sprinkled over and the urine of a girl should be washed."