Any references for Wall's Lemma of exactness?

At title goes, I read the following lemma in Bredon's book (GTM139 Topology and Geometry Page 189). But I find that I have never seen it in any other texts on algebraic topology or homological algebra. So I would like to ask the references for it.

• To add to Paul Frost's references, this is §26, Exer. 1 in Elements of algebraic topology by Munkres, although it is left as an exercise. You can also try to prove this lemma using spectral sequences like I did, but it doesn't seem very straightforward. Aug 23, 2018 at 0:29