@article{COMIM_2013__21_1_a0,
     author = {Friedrich, Thomas},
     title = {Cocalibrated $G_2$-manifolds with {Ricci} flat characteristic connection},
     journal = {Communications in Mathematics},
     pages = {1--13},
     publisher = {mathdoc},
     volume = {21},
     number = {1},
     year = {2013},
     mrnumber = {3067118},
     zbl = {06202721},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/COMIM_2013__21_1_a0/}
}