Transverse voltages and reciprocity theorem in magnetic fields for high   T_c superconductors
  We have tested four-point methods of the Hall effect measurement on BiSrCaCuO (2223) polycrystal and also the validity of the magnetic field form of the reciprocity theorem. We found that different types of determination of the Hall resistance using various combination of measured resistances provide different value of it. We have separated two parts of the resistance combinations, which are even and odd in magnetic field, respectively. The odd part, which is equivalent to the Hall effect, is equal for all formulae used. The even part of transverse resistance varies in different formulae. The magnetic field form of the reciprocity theorem is not valid. Models for explanation of this violation are also discussed. 
I. Jane\v{c}ek, P. Va\v{s}ek