  A version of the configuration interaction method, which has been recently
developed to deal with large number of valence electrons, has been used to
calculate magnetic dipole and electric quadrupole hyperfine structure constants
for a number of states of erbium and fermium. Calculations for fermium are done
for extracting nuclear moments of Fm isotopes from recent and future
measurements. Calculations for erbium, which has electronic structure similar
to those of fermium, are done to study the accuracy of the method.
