SPIN WAVE ANALYSIS OF THE TWO-DIMENSIONAL HEISENBERG ANTIFERROMAGNETS Rb2MnCl4 AND (CH3NH3)2MnCl4 B. Schröder, V. Wagner, N. Lehner and R. Geick J. Phys. Colloques, 39 C6 (1978) C6-753-C6-754 DOI: 10.1051/jphyscol:19786336