References
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Wessel, P. (2010), Tools for analyzing intersecting tracks: the x2sys
package. *Computers and Geosciences*, **36**, 348-354, https://www.researchgate.net/publication/220164039_Tools_for_analyzing_intersecting_tracks_The_x2sys_package.

Wessel, P. (1989), XOVER: A cross-over error detector for track data,
*Computers and Geosciences*, **15**\ (3), 333-346, https://doi.org/10.1016/0098-3004(89)90044-7.
