Doppler limited laser spectroscopy on hafnium lines. Part I: Hyperfine structure of even-parity levelsS. Bouazza, M. Fienhold, G. H. Guthöhrlein, H. O. Behrens and J. DembczynskiEur. Phys. J. D, 6 3 (1999) 303-309DOI: https://doi.org/10.1007/s100530050313