1. Remarks on positive frequency and hamiltonians in expanding universes

   • S. A. Fulling

   Research Articles Pages: 807 - 824

2. Strong gravity with torsion and the Cabibbo angle

   • V. De Sabbata
   • M. Gasperini

   Research Articles Pages: 825 - 831

3. Null surface quantization and quantum theory of massless fields in asymptotically flat space-time

   • V. P. Frolov

   Research Articles Pages: 833 - 852

4. Riemannian-Maxwellian invertible structures in general relativity

   • R. Debever
   • R. G. McLenaghan
   • N. Tariq

   Research Articles Pages: 853 - 879

5. Errata

   Erratum Pages: 881 - 881