Order:
  1.  6
    Interest Group in Pure and Applied Logics.D. Gabbay, R. D. Queiroz & H. J. Ohlbach - 1995 - Logic Journal of the IGPL 3 (1):151-152.
  2. Maria Manzano, Extensions of First-Order Logic.H. J. Ohlbach - 1998 - Journal of Logic Language and Information 7:389-391.