# Galileo's pendulum and any references

In some texts about the simple pendulum we use to see references about some "experiments" Galileo Galilei did realize and whereby he found some important results, including that the period of the pendulum is proportional to the square root of the lenght of the (stem of the) pendulum. I would like to know if there is any book ou document wrote by Galileo (on the Dialogues or the Discourses) where I can find the explanation about these experiments realized by Galileo.