The first journal publication relating to my PhD describes fracture toughness measurements made at ambient conditions, their anisotropy, and an anisotropic modification to the maximum energy release rate criterion, used to determine when crack paths will deflect into a bedding-parallel direction.

Chandler, M. R., P. G. Meredith, N. Brantut, and B. R. Crawford (2016), Fracture toughness anisotropy in shale, J. Geophys. Res. Solid Earth, 121, 1706–1729, doi:10.1002/2015JB012756.