  Let $\tilde{\mathfrak g}$ be an affine Lie algebra of the type
$A_\ell^{(1)}$. We find a combinatorial basis of Feigin-Stoyanovsky's type
subspace $W(\Lambda)$ given in terms of difference and initial conditions.
Linear independence of the generating set is proved inductively by using
coefficients of intertwining operators. A basis of $L(\Lambda)$ is obtained as
an "inductive limit" of the basis of $W(\Lambda)$.
