On uniqueness for Franklin series with a convergent subsequence of partial sums

We show that if the partial sums $S_{n_i}(x)=\sum_{k=0}^{n_i}a_kf_k(x)$ of a Franklin series $\sum_{k=0}^{\infty}a_kf_k(x)$, where $\sup_i{n_i}/(n_{i-1})<\infty$, converge in measure to a bounded function $f$ and $\sup_i|S_{n_i}(x)|<\infty$ for $ x\not\in B$, where $B$ is some countable set, then this series is the Fourier-Franklin series of $f$. Bibliography: 24 titles.