Paper references

[smithara]

Include links to relevant papers.

Examples:

MCO_SHA_2C: https://doi.org/10.1186/s40623-018-0896-3

MCO_SHA_2D: https://doi.org/10.5047/eps.2013.07.005

MLI_SHA_2D: https://doi.org/10.5047/eps.2013.07.008

MMA_SHA_2F: https://doi.org/10.5047/eps.2013.09.003

MIO_SHA_2D: https://doi.org/10.5047/eps.2013.08.006
https://doi.org/10.1186/s40623-016-0481-6
https://geomag.colorado.edu/geomagnetic-and-electric-field-models