Oblique incidence of semi-guided waves on rectangular slab waveguide discontinuities: A vectorial QUEP solver
M. Hammer, Optics Communications 338 (2014) 447–456.

General relation for group delay and the relevance of group delay for refractometric sensing
H.J.W.M. Hoekstra, M. Hammer, Journal of the Optical Society of America B 31 (2014).