- was useful to overcome submodule error for 'pybind11' in github.com/tdegeus/pybind11_examples
- the command mentioned in Edit 2, 'git submodule sync' is crucial
T. Mossakowski, O. Kutz, and M. Codescu. Proc. of the Theory Day in Computer Science (DACS-2014), satellite workshop of ICTAC-2014, University of Bucharest, September 15-16, 2014, (2014)