  We construct embeddings of boundary algebras B into ZF algebras A. Since it
is known that these algebras are the relevant ones for the study of quantum
integrable systems (with boundaries for B and without for A), this connection
allows to make the link between different approaches of the systems with
boundaries. The construction uses the well-bred vertex operators built
recently, and is classified by reflection matrices. It relies only on the
existence of an R-matrix obeying a unitarity condition, and as such can be
applied to any infinite dimensional quantum group.
