Citing GIBBON
Cite the Journal of Open Source Software paper: 
Moerman, (2018). GIBBON: The Geometry and Image-Based Bioengineering add-On. Journal of Open Source Software, 3(22), 506, https://doi.org/10.21105/joss.00506
Cite the Journal of Open Source Software paper:
Moerman, (2018). GIBBON: The Geometry and Image-Based Bioengineering add-On. Journal of Open Source Software, 3(22), 506, https://doi.org/10.21105/joss.00506