diff --git a/SC3016.md b/SC3016.md
index 074525c..de3f049 100644
--- a/SC3016.md
+++ b/SC3016.md
@@ -12,8 +12,7 @@ fi
 
 ### Correct code:
 
-Either switch to bash:
-
+Either switch to bash or ksh, or use:
 ```sh
 #!/bin/sh
 if [ -n "${STY+x}" ]
@@ -26,7 +25,7 @@ fi
 
 Your script uses a shell feature not supported by the shebang. Either rewrite the script to be portable, or change the shebang to explicitly require a shell like Bash.
 
-In this case, `[ -v variable ]` to check if a variable is set can be replaced with `[ -n "${variable+x}" ]` which uses the "alternative value if set" parameter expansion syntax to accomplish the same thing.
+In this case, `[ -v variable ]`, which checks if a variable is set, is [not specified by POSIX](https://pubs.opengroup.org/onlinepubs/9699919799/utilities/test.html).  It can be replaced with the portable `[ -n "${variable+x}" ]`, which uses the "alternative value if set" [parameter expansion](https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_06_02) syntax to accomplish the same thing.
 
 ### Exceptions: