Resolution No.25 (1971): IGRF

The IAGA recommends

1. that the present International Geomagnetic Reference Field (IGRF) be retained until at least 1973.5
2. that future evaluations should always include an assessment of the IGRF and
3. that comparisons between observed and computed values should always include an assessment of the IGRF and
4. that results using other reference fields should also be compared with IGRF.