1. Beitrage zur Kentniss des Wesens der Sakular-Variation des Erdmagnetismus;Bauer,1895
2. Analysis of present geomagnetic field for comparison with paleomagnetic results;Cox,1962
3. Some features of secular variation of the geomagnetic field;DuBois,1967
4. Archeomagnetic results from the United States, 10,000 B.C. to present and with some data from Mesoamerica;DuBois,1987
5. Results from Japan;Hirooka,1983