  We introduce a specialization technique in order to study monomial ideals
that are generated in degree two by using our earlier results about Ferrers
ideals. It allows us to describe explicitly a cellular minimal free resolution
of various ideals including any strongly stable and any squarefree strongly
stable ideal whose minimal generators have degree two. In particular, this
shows that threshold graphs can be obtained as specializations of Ferrers
graphs, which explains their similar properties.
