Update README.md

Author: firefly-cpp

README.md

@@ -261,12 +261,13 @@ This repository serves as a list of knowledge for researchers working in Computa
 
 - [ast-monitor](https://github.com/firefly-cpp/AST-Monitor) - A wearable Raspberry Pi computer for cyclists.
 - [ast-tdl](https://github.com/firefly-cpp/ast-tdl) - Training Description Language.
+- [gpx](https://cran.r-project.org/web/packages/gpx/index.html) - Process GPX Files into R Data Structures.
 - [gpxpy](https://github.com/tkrajina/gpxpy) - A simple Python library for parsing and manipulating GPX files.
 - [openant](https://github.com/Tigge/openant) - ANT and ANT-FS Python Library.
+- [python-tcxparser](https://github.com/vkurup/python-tcxparser) - Simple parser for Garmin TCX files.
 - [sport-activities-features](https://github.com/firefly-cpp/sport-activities-features) - A minimalistic toolbox for extracting features from sport activity files written in Python.
 - [tcxreader](https://github.com/alenrajsp/tcxreader) - Reader / parser for Garmin's TCX file format.
 - [tcx2gpx](https://gitlab.com/nshephard/tcx2gpx) - Python package for converting tcx GPS files to gpx files.
-- [python-tcxparser](https://github.com/vkurup/python-tcxparser) - Simple parser for Garmin TCX files.
 
 ## Web applications 🌐