Given a three- dimensional wavefunction (phi) (x, y, z),

what is the probability of simultaneously measuring

momentum and position to obtain the results

a < y < b and p' < Pz < P" ?

I know that integration of the square norm of the wavefunction of the region

under question yields the probability for finding the position or momentum

of the system described by the wavefunction. But how do you do this

for simultaneous measurements of momentum and position?

Thanks!