Note public key recovery article

README.md

@@ -2979,6 +2979,8 @@ Before you unmount your backup, ask yourself if you should make another one just
 
 - If you receive the error, `gpg: 0x0000000000000000: skipped: Unusable public key`, `signing failed: Unusable secret key`, or `encryption failed: Unusable public key` the sub-key may be expired and can no longer be used to encrypt nor sign messages. It can still be used to decrypt and authenticate, however.
 
+- If you lost your GPG public key and need to recover it from YubiKey, follow [this guide](https://www.nicksherlock.com/2021/08/recovering-lost-gpg-public-keys-from-your-yubikey/)
+
 - Refer to Yubico article [Troubleshooting Issues with GPG](https://support.yubico.com/hc/en-us/articles/360013714479-Troubleshooting-Issues-with-GPG) for additional guidance.
 
 # Alternatives