Normal extensions of a singular multipoint differential operator of first order

In this work, we describe all normal extensions of the minimal operator generated by linear singular multipoint formally normal differential expression $l=(l_1,l_2,l_3)$, $l_k=frac{d}{dt}+A_k$ with selfadjoint operator coefficients $A_k$ in a Hilbert space. This is done as a direct sum of Hilbert spaces of vector-functions $$ L_2(H,(-infty ,a_1))oplus L_2(H,(a_2,b_2)) oplus L_2(H,(a_3,+infty)) $$ where $-infty