diff --git a/include/mp/nl-reader.h b/include/mp/nl-reader.h
index cf76b834d..dfa56862c 100644
--- a/include/mp/nl-reader.h
+++ b/include/mp/nl-reader.h
@@ -4,7 +4,7 @@
  NL is a format for representing optimization problems such as linear,
  quadratic, nonlinear, complementarity and constraint programming problems
  in discrete or continuous variables. It is described in the technical report
- "Writing .nl Files" (http://www.cs.sandia.gov/~dmgay/nlwrite.pdf).
+ "Writing .nl Files" (https://ampl.github.io/nlwrite.pdf).
 
  This is a complete reusable C++ implementation of an NL reader.
 
diff --git a/nl-writer2/include/mp/nl-feeder.h b/nl-writer2/include/mp/nl-feeder.h
index 5ff497228..dd1d4950c 100644
--- a/nl-writer2/include/mp/nl-feeder.h
+++ b/nl-writer2/include/mp/nl-feeder.h
@@ -8,7 +8,7 @@
  NL is a format for representing optimization problems such as linear,
  quadratic, nonlinear, complementarity and constraint programming problems
  in discrete or continuous variables. It is described in the technical report
- "Writing .nl Files" (http://www.cs.sandia.gov/~dmgay/nlwrite.pdf).
+ "Writing .nl Files" (https://ampl.github.io/nlwrite.pdf).
 
  Usage: recommended via mp::NLSOL class.
 
diff --git a/nl-writer2/include/mp/nl-solver.h b/nl-writer2/include/mp/nl-solver.h
index 30202e49a..cbef4000c 100644
--- a/nl-writer2/include/mp/nl-solver.h
+++ b/nl-writer2/include/mp/nl-solver.h
@@ -9,7 +9,7 @@
  NL is a format for representing optimization problems such as linear,
  quadratic, nonlinear, complementarity and constraint programming problems
  in discrete or continuous variables. It is described in the technical report
- "Writing .nl Files" (http://www.cs.sandia.gov/~dmgay/nlwrite.pdf).
+ "Writing .nl Files" (https://ampl.github.io/nlwrite.pdf).
 
 
  Copyright (C) 2024 AMPL Optimization, Inc.
diff --git a/nl-writer2/include/mp/nl-writer2.h b/nl-writer2/include/mp/nl-writer2.h
index 61690aead..c916a0021 100644
--- a/nl-writer2/include/mp/nl-writer2.h
+++ b/nl-writer2/include/mp/nl-writer2.h
@@ -4,7 +4,7 @@
  NL is a format for representing optimization problems such as linear,
  quadratic, nonlinear, complementarity and constraint programming problems
  in discrete or continuous variables. It is described in the technical report
- "Writing .nl Files" (http://www.cs.sandia.gov/~dmgay/nlwrite.pdf).
+ "Writing .nl Files" (https://ampl.github.io/nlwrite.pdf).
 
  This is a complete reusable C++ implementation of an NL writer.
 
diff --git a/nl-writer2/include/mp/unused/nl-feeder-abstract.h b/nl-writer2/include/mp/unused/nl-feeder-abstract.h
index 2f57d24a4..25d6309d5 100644
--- a/nl-writer2/include/mp/unused/nl-feeder-abstract.h
+++ b/nl-writer2/include/mp/unused/nl-feeder-abstract.h
@@ -7,7 +7,7 @@
  NL is a format for representing optimization problems such as linear,
  quadratic, nonlinear, complementarity and constraint programming problems
  in discrete or continuous variables. It is described in the technical report
- "Writing .nl Files" (http://www.cs.sandia.gov/~dmgay/nlwrite.pdf).
+ "Writing .nl Files" (https://ampl.github.io/nlwrite.pdf).
 
  Usage: recommended via mp::NLSOL class.
  See the MP2NL driver for example implementation.
diff --git a/nl-writer2/src/nl-writer2.cc b/nl-writer2/src/nl-writer2.cc
index 991e9570d..22847c05f 100644
--- a/nl-writer2/src/nl-writer2.cc
+++ b/nl-writer2/src/nl-writer2.cc
@@ -4,7 +4,7 @@
  NL is a format for representing optimization problems such as linear,
  quadratic, nonlinear, complementarity and constraint programming problems
  in discrete or continuous variables. It is described in the technical report
- "Writing .nl Files" (http://www.cs.sandia.gov/~dmgay/nlwrite.pdf).
+ "Writing .nl Files" (https://ampl.github.io/nlwrite.pdf).
 
  This is a complete reusable C++ implementation of an NL writer.