@article{10_4153_CJM_2010_059_2,
     author = {Calvi\~no-Louzao, E. and Garc{\'\i}a-R{\'\i}o, E. and V\'azquez-Lorenzo, R.},
     title = {Riemann {Extensions} of {Torsion-Free} {Connections} with {Degenerate} {Ricci} {Tensor}},
     journal = {Canadian journal of mathematics},
     pages = {1037--1057},
     year = {2010},
     volume = {62},
     number = {5},
     doi = {10.4153/CJM-2010-059-2},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-2010-059-2/}
}