Let L be an oriented tame link in the three sphere S3. We study the Murasugi signature, σ(L), and the nullity, η(L). It is shown that σ(L) is a locally flat topological concordance invariant and that η(L) is a topological concordance invariant (no local flatness assumption here). Known results about the signature are re-proved (in some cases generalized) using branched coverings.
Kauffman, L. H., & Taylor, L. R. (1976). Signature of Links. Trans. Amer. Math. Soc., 216, 351–365. https://doi.org/10.1090/S0002-9947-1976-0388373-0