@article{02105216, title = {Tetra and Didi, the cosmic spectral twins.}, journal = {Geometry \& Topology}, volume = {8}, year = {2004}, pages = {1227-1242}, doi = {10.2140/gt.2004.8.1227}, zbl = {1091.58021}, language = {en}, url = {http://dml.mathdoc.fr/item/02105216} }
Doyle, Peter G.; Rossetti, Juan Pablo. Tetra and Didi, the cosmic spectral twins.. Geometry & Topology, Tome 8 (2004) pp. 1227-1242. doi : 10.2140/gt.2004.8.1227. http://gdmltest.u-ga.fr/item/02105216/