The Hybrid Activities of the Pierre Auger Observatory
  The Pierre Auger Observatory detects ultra-high energy cosmic rays by implementing two complementary air-shower techniques. The combination of a large ground array and fluorescence detectors, known as the hybrid concept, means that a rich variety of measurements can be made on a single shower, providing much improved information over what is possible with either detector alone. In this paper I describe the hybrid reconstruction approach and the latest hybrid measurements. 
Miguel Mostafa (Pierre Auger Collaboration)