diff --git a/pkcs11-tools.md b/pkcs11-tools.md
index 81371df..ca06998 100644
--- a/pkcs11-tools.md
+++ b/pkcs11-tools.md
@@ -3,6 +3,8 @@
 * GnuTLS p11tool
 * p11-kit
 
+----
+
 ```shell
 $ pkcs11-tool --module /Library/OpenSC/lib/opensc-pkcs11.so -I
 Cryptoki version 3.0
@@ -11,6 +13,17 @@ Library          OpenSC smartcard framework (ver 0.25)
 Using slot 0 with a present token (0x0)
 ```
 
+```shell
+$ pkcs11-tool --module /usr/local/lib/libykcs11.dylib --show-info
+Cryptoki version 2.40
+Manufacturer     Yubico (www.yubico.com)
+Library          PKCS#11 PIV Library (SP-800-73) (ver 2.31)
+Using slot 0 with a present token (0x0)
+```
+
+----
+
+
 ```shell
 $ p11tool --provider=/Library/OpenSC/lib/opensc-pkcs11.so --info
 Object 0:
@@ -20,4 +33,12 @@ Object 0:
 	Flags: CKA_EXTRACTABLE; 
 	ID: 01
 ...
-```
\ No newline at end of file
+```
+
+
+
+<br>
+
+# Reference
+1. https://developers.yubico.com/yubico-piv-tool/YKCS11/Supported_applications/pkcs11tool.html
+