Joshua 10: 13: And the sun stood still, and the moon stayed, until the people had avenged themselves upon their enemies. Is not this written in the book of Jasher? So the sun stood still in the midst of heaven, and hasted not to go down about a whole day.
2 Samuel 1: 18: (Also he bade them teach the children of Judah the use of the bow: behold, it is written in the book of Jasher.)
The link below provides the English translation of the Book of Jasher.