diff --git a/yubikey-ssh-pkcs11.md b/yubikey-ssh-pkcs11.md
index 95fcc5f..f1b4178 100644
--- a/yubikey-ssh-pkcs11.md
+++ b/yubikey-ssh-pkcs11.md
@@ -6,7 +6,15 @@ ssh-keygen -D /Library/OpenSC/lib/opensc-pkcs11.so
 ssh -I /Library/OpenSC/lib/opensc-pkcs11.so root@example.com
 ```
 
+`~/.ssh/config`
+
+```plain
+PKCS11Provider /Library/OpenSC/lib/opensc-pkcs11.so
+```
+
+<br>
 
 # Reference
 1. https://github.com/tpm2-software/tpm2-pkcs11/blob/master/docs/SSH.md
-1. https://github.com/ThomasHabets/simple-tpm-pk11
\ No newline at end of file
+1. https://github.com/ThomasHabets/simple-tpm-pk11
+1. https://ubuntu.com/server/docs/smart-card-authentication-with-ssh