@article{GDZPPN002100940,
title = {The e-invariant and the spectrum of the Lapacian for compact nilmanifolds covered by Heisenberg groups.},
journal = {Inventiones mathematicae},
volume = {75},
year = {1984},
pages = {101-112},
zbl = {0558.55010},
url = {http://dml.mathdoc.fr/item/GDZPPN002100940}
}
Singhof, W.; Deninger, Ch. The e-invariant and the spectrum of the Lapacian for compact nilmanifolds covered by Heisenberg groups.. Inventiones mathematicae, Tome 75 (1984) pp. 101-112. http://gdmltest.u-ga.fr/item/GDZPPN002100940/