@article{GDZPPN002090260,
title = {Perturbation of Harmonic Spaces and Construction of Semigroups.},
journal = {Inventiones mathematicae},
volume = {20},
year = {1973},
pages = {149-164},
zbl = {0258.31005},
url = {http://dml.mathdoc.fr/item/GDZPPN002090260}
}
Hansen, W. Perturbation of Harmonic Spaces and Construction of Semigroups.. Inventiones mathematicae, Tome 20 (1973) pp. 149-164. http://gdmltest.u-ga.fr/item/GDZPPN002090260/