@article{10_2307_121098,
     author = {Sergei Merkulov and Lorenz Schwachh\"ofer},
     title = {Classification of irreducible holonomies of torsion-free affine connections},
     journal = {Annals of mathematics},
     year = {1999},
     volume = {150},
     number = {1},
     doi = {10.2307/121098},
     zbl = {0992.53038},
     url = {http://geodesic.mathdoc.fr/articles/10.2307/121098/}
}