1. Second-order scalar-tensor field equations in a four-dimensional space

   • Gregory Walter Horndeski

   OriginalPaper Pages: 363 - 384

2. An extended approach to the field-theoretical time operators

   • E. Papp

   OriginalPaper Pages: 385 - 389

3. A new approach to interacting fields

   • C. Von Westenholz

   OriginalPaper Pages: 391 - 433