diff --git a/SC3026.md b/SC3026.md
index 5003074..d634cb4 100644
--- a/SC3026.md
+++ b/SC3026.md
@@ -16,7 +16,7 @@ echo foo-[!0]*.jpg
 
 `[^c]` is frequently used in most regular expression variants to mean "any character except `c`". Ksh and Bash adopted it for globs as well.
 
-However, strictly speaking, the only range complement syntax guaranteed to be supported across shells is `[!c]`. Dash used to support `[^c]` when compiled with `fnmatch` and `glob` from glibc, but it was considered as a [bug](https://lore.kernel.org/dash/09fd70edcf08c75b4f9f2e158e3e6c0832d35d90.camel@scientia.org/t/#u) and fixed in version 0.5.12. Busybox has a similar [bug 14516](https://bugs.busybox.net/show_bug.cgi?id=14516).
+However, strictly speaking, the only range complement syntax guaranteed to be supported across shells is `[!c]`. POSIX explicitly states that behavior of `[^c]` is unspecified. Dash used to support `[^c]` when compiled with `fnmatch` and `glob` from glibc, but it was considered as a [bug](https://lore.kernel.org/dash/09fd70edcf08c75b4f9f2e158e3e6c0832d35d90.camel@scientia.org/t/#u) and fixed in version 0.5.12. Busybox has a similar [bug 14516](https://bugs.busybox.net/show_bug.cgi?id=14516).
 
 ### Exceptions:
 
@@ -26,5 +26,6 @@ Or just rewrite it to be on the technically correct side.
 
 ### Related resources:
 
-* [2.13.1 Patterns Matching a Single Character](https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_13_01) in the Shell and Utilities (XCU) volume of POSIX.1-2017
+* [2.13.1 Patterns Matching a Single Character](https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_13_01) in the Shell and Utilities (XCU) volume of POSIX.1-2017.
+* [0001558: require `[^...]` in addition to `[!...]` for bracket expression negation](https://www.austingroupbugs.net/view.php?id=1558) POSIX enhancement request was rejected.
 * Help by adding links to BashFAQ, StackOverflow, man pages, POSIX, etc!