A Formula for the Rotation Periods of the Planets & Asteroids
  The note presents a formula for the prediction of the rotation periods of the planets and asteroids. This formula, which is like the Titius-Bode law, gives a good agreement with the rotation periods of most planets, shows that Venus is retrograde, and that there must be five objects between Mars and Jupiter. This formula may be of some relevance in understanding the dynamics of the early solar system. 
Subhash Kak