4A_74/2019 vom 31. Juli 2019 [Arbitral tribunal not obliged to call the author of an important letter as a witness, nor obliged to obtain a witness statement from an individual whose appearance it requested] - ASA Bulletin View 4A_74/2019 vom 31. Juli 2019 [Arbitral tribunal not obliged to call the author of an important letter as a witness, nor obliged to obtain a witness statement from an individual whose appearance it requested] by - ASA Bulletin 4A_74/2019 vom 31. Juli 2019 [Arbitral tribunal not obliged to call the author of an important letter as a witness, nor obliged to obtain a witness statement from an individual whose appearance it requested] 38 4 ASA Bulletin