The Maltravieso cave, year 1960
Carlos Callejo, year 1950
The Discovery Room (disappeared) in the Maltravieso cave, year 1951
Carlos Callejo and Martín Almagro inside the Maltravieso cave, year 1960
C. Callejo and A. Márquez inside the Maltravieso cave, year 1968
Studies published in the nineties
C. Callejo, Martín Almagro and Jordá inside the Maltravieso cave, year 1960
C. Callejo's correspondance with national and international researchers
Recent research