  This paper has been withdrawn
  Any real number $x$ in the unit interval can be expressed as a continued
fraction $x=[n_1,...,n_{_N},...]$. Subsets of zero measure are obtained by
imposing simple conditions on the $n_{_N}$. By imposing $n_{_N}\le m \forall
N\in \zN$, Jarnik defined the corresponding sets $E_m$ and gave a first
estimate of $d_H(E_m)$, $d_H$ the Hausdorff dimension. Subsequent authors
improved these estimates. In this paper we deal with $d_H(E_m)$ and $d_H(F_m)$,
$F_m$ being the set of real numbers for which ${\sum_{i=1}^N n_i\over N}\le m$.
