Link to each version of the specification

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/docs/psa/index.html b/docs/psa/index.html
index 67b0ae3..9288ff2 100644
--- a/docs/psa/index.html
+++ b/docs/psa/index.html
@@ -3,6 +3,10 @@
 <h2 id="application-programming-interface">Application programming interface</h2>
 <p>The PSA Cryptography API is a C programming interface for applications that wish to store cryptographic keys and use them to perform cryptographic operations.</p>
 <p><strong>Reference documentation</strong>: <a href="../html/index.html">HTML</a>, <a href="../PSA_Cryptography_API_Specification.pdf">PDF</a></p>
+<p>Past versions:</p>
+<ul>
+<li>1.0.1: <a href="../1.0.1/html/index.html">HTML</a>, <a href="../1.0.1/PSA_Cryptography_API_Specification.pdf">PDF</a></li>
+</ul>
 <p><strong>Reference implementation</strong>: <a href="https://github.com/ARMmbed/mbed-tls">Mbed TLS</a></p>
 <h2 id="hardware-abstraction-layer">Hardware abstraction layer</h2>
 <h3 id="unified-driver-interface">Unified driver interface</h3>
diff --git a/docs/psa/index.md b/docs/psa/index.md
index d575f94..d67ec86 100644
--- a/docs/psa/index.md
+++ b/docs/psa/index.md
@@ -11,6 +11,12 @@
 [HTML](../html/index.html),
 [PDF](../PSA_Cryptography_API_Specification.pdf)
 
+Past versions:
+
+* 1.0.1:
+  [HTML](../1.0.1/html/index.html),
+  [PDF](../1.0.1/PSA_Cryptography_API_Specification.pdf)
+
 **Reference implementation**: [Mbed TLS](https://github.com/ARMmbed/mbed-tls)
 
 ## Hardware abstraction layer