An optical spectroscopic survey of the 3CR sample of radio galaxies with z < 0.3 - IV. Discovery of the new spectroscopic class of relic radio galaxies
A. Capetti, S. Buttiglione, D. J. Axon, A. Robinson, A. Celotti, R. D. Baldi, M. Chiaberge, F. D. Macchetto and W. B. Sparks
