diff --git a/1984/mullender/README.md b/1984/mullender/README.md
index ca39909e5..421e8d183 100644
--- a/1984/mullender/README.md
+++ b/1984/mullender/README.md
@@ -245,7 +245,7 @@ with the `calls` instruction. This instruction uses the first (2-byte)
 [word](https://en.wikipedia.org/wiki/Word_(computer_architecture)) of the called
 routine as a mask of
 [registers](https://en.wikipedia.org/wiki/Processor_register) that are to be
-saved on the [stack](https://en.wikipedia.org/wiki/Stack(abstract_data_type)).
+saved on the [stack](https://en.wikipedia.org/wiki/Call_stack).
 In other words, on the VAX the first word can be anything. On the
 [PDP](https://en.wikipedia.org/wiki/Programmed_Data_Processor), the first word
 is a [branch](https://en.wikipedia.org/wiki/Branch_(computer_science))
diff --git a/1984/mullender/index.html b/1984/mullender/index.html
index fb6be18b3..30977fc80 100644
--- a/1984/mullender/index.html
+++ b/1984/mullender/index.html
@@ -566,7 +566,7 @@ with the <code>calls</code> instruction. This instruction uses the first (2-byte
 <a href="https://en.wikipedia.org/wiki/Word_(computer_architecture)">word</a> of the called
 routine as a mask of
 <a href="https://en.wikipedia.org/wiki/Processor_register">registers</a> that are to be
-saved on the <a href="https://en.wikipedia.org/wiki/Stack(abstract_data_type)">stack</a>.
+saved on the <a href="https://en.wikipedia.org/wiki/Call_stack">stack</a>.
 In other words, on the VAX the first word can be anything. On the
 <a href="https://en.wikipedia.org/wiki/Programmed_Data_Processor">PDP</a>, the first word
 is a <a href="https://en.wikipedia.org/wiki/Branch_(computer_science)">branch</a>