(EN) open-spf.org, http://www.open-spf.org/SRS/. URL consultato il 27 ottobre 2022.
«SPF "breaks" email forwarding. SRS is a way to fix it. SRS is a simple way for forwarding MTAs to rewrite the sender address. The original concept was published in draft-mengwong-sender-rewrite and further expanded on in a paper by Shevek.»