HFS MEASUREMENTS IN THE 4 s4p 1P1 STATE OF 43Ca BY THE LEVEL CROSSING TECHNIQUE H.-J. KLUGE, E.-W. OTTEN and G. ZIMMERMANN J. Phys. Colloques, 30 C1 (1969) C1-15-C1-17 DOI: 10.1051/jphyscol:1969103