1. A.F.Andreev, Zh. Eksp. Teor. Fiz. 46 (1964) 1823 [Sov. Phys. JETP 19 (1964) 1228].
2. I.O. Kulik, Zh. Eksp. Teor. Fiz. 57 (1969) 1745 (Sov. Phys. JETP 30 (1970) 944); J. Bardeen, J.L. Johnson, Phys. Rev. B 5 (1972) 72; C.W.J. Beenakker, Phys. Rev. Lett. 67 (1991). 3836.
3. A.F. Morpurgo, F. Beltram, Phys. Rev. B 50 (1994) 1325; see also C.J. Lambert, A. Martin, J. Phys. C. 6 (1994) L221.
4. A.F. Morpurgo et al., Appl. Phys. Lett. 70 (1997) 1435; Phys. Rev. Lett. 78 (1997) 2636.
5. The voltage corresponds to the electron energy, since the inelastic scattering length in the 2DEG, ≈10μm, is substantially longer than the channel length.