@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/