1. Micha³ Eckstein, Nicolas Franco
Causal structure for noncommutative geometry
Frontiers of Fundamental Physics, vol. 14, pp. 138-xxx (2015).

2. Nicolas Franco, Micha³ Eckstein
Noncommutative geometry, Lorentzian structures and causality
in “Mathematical Structures of the Universe”, eds. M. Eckstein, M. Heller, S.J. Szybka, Copernicus Center Press (2014), pp. 315-340

3. Nicolas Franco
Towards a noncommutative version of Gravitation
AIP Conference Proceedings, vol. 1241, pp. 588-594 (2010).

4. Nicolas Franco
Survey of Gravity in Non-Commutative Geometry
Topology, Quantum fields theory & Cosmology, Hermann, pp. 313-329 (2009).