A generalization of the Landauer formula for multiple terminals is the Landauer–Büttiker formula, proposed by Markus Büttiker [ de ]. If terminal j has voltage V j (that is, its chemical potential is e V j and differs from terminal i chemical potential), and T i , j is the sum of transmission probabilities from terminal i to terminal j (note that T i , j may or may not equal T j , i depending on the presence of a magnetic field), the net current leaving terminal i is