Resolution No.21 (1973): Importance of data and records of observation in previous epochs
IAGA, recognising that data and records of observations made in previous epochs will be of great importance in the study of the long-term variation of the aeronomic and geomagnetic aspects of the earth and its environment, IAGA recommends that each country take appropriate action to catalogue and to preserve such historically important data to advise the scientific community of their availability.