Actually I need to be having a documented proof.
Proof for what? As Centaurus says, in aircraft with normal brake pedal configuration (e.g. toe brakes), one uses toes for rudder control until touch down and then after nose gear touchdown or when required for braking slides his feet slightly up so toes can reach the brake pedals.
Some info from 737 FCTM - nothing on feet position, although common sense would dictate extremely careful use of the procedure above:
Braking with Antiskid Inoperative
Antiskid Inoperative - Landing
When the antiskid system is inoperative, the following techniques apply:
• ensure that the nose wheels are on the ground and the speedbrakes are
extended before applying the brakes
• initiate wheel braking using very light pedal pressure and increase
pressure as ground speed decreases
• apply steady pressure.
When the antiskid system is inoperative, the NNC tells the flight crew that they
should not pump the brakes. This is because each time the brakes are released, the
required stopping distance is increased. Also, each time the brakes are reapplied,
the probability of a skid is increased.
Flight testing has demonstrated that braking effectiveness on a wet grooved
runway is similar to that of a dry runway. However caution must be exercised
when braking on any wet, ungrooved portions of the runway with antiskid
inoperative to avoid tire failure.