Isometric embeddings of coinvariant subspaces of the shift operator

Let $\theta$ be an inner function. The main aim of the paper is to describe all positive measures on the unit circle $\mathbb T$ such that $\int_\mathbb T|f|^2\,d\mu=\|f\|^2_{H^2}$ for all continuous functions $f\in H^2\ominus\theta H^2$. Bibl. 8 titles.