Getting GPX files from Garmin Connect – The English Cyclist
GitHub - scubajorgen/FitReader: Library for reading the ANT FIT file format. This format is used by Garmin GPSses. See http://blog.studioblueplanet.net/?page_id=468
FIT Protocol | FIT SDK | Garmin Developers
Getting waypoints into the Garmin GPS 60 using .loc file and GPSBabel