  This short note presents works done in collaboration with S. Pakuliak (JINR,
Dubna) and N. Slavnov (Steklov Math. Inst., Moscow). It is a summary of the
articles arXiv:1412.6037, arXiv:1501.07566, arXiv:1502.01966 and
arXiv:1503.00546. Here are mentioned only references used for our calculations.
A detailed list of references can be found in our articles mentionned here.
