ON THE ANISOTROPY OF THE RECOILLESS FRACTION IN FeCO3 AT 4.2 K D.L. NAGY, K. KULCSÁR, H. SPIERING et R. ZIMMERMAN J. Phys. Colloques, 35 C6 (1974) C6-385-C6-387 DOI: 10.1051/jphyscol:1974672