@article{10_4064_cm7002s_11_2016,
     author = {Carlo Alberto Mantica and Luca Guido Molinari},
     title = {Simple conformally recurrent space-times are conformally recurrent pp-waves},
     journal = {Colloquium Mathematicum},
     pages = {9--20},
     publisher = {mathdoc},
     volume = {150},
     number = {1},
     year = {2017},
     doi = {10.4064/cm7002s-11-2016},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/cm7002s-11-2016/}
}