diff --git a/Makefile b/Makefile
index 10f380f..685c73a 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,6 @@
 # pgmp -- pgxs-based makefile
 #
-# Copyright (C) 2011-2020 Daniele Varrazzo
+# Copyright (C) 2011 Daniele Varrazzo
 #
 # This file is part of the PostgreSQL GMP Module
 #
diff --git a/bench/benchmark.py b/bench/benchmark.py
index 278ac9b..8cfd210 100755
--- a/bench/benchmark.py
+++ b/bench/benchmark.py
@@ -1,7 +1,7 @@
 #!/usr/bin/env python
 """Script to perform comparisons between pmpz and other data types.
 
-Copyright (C) 2011-2020 - Daniele Varrazzo
+Copyright (C) 2011 - Daniele Varrazzo
 """
 import sys
 
diff --git a/bench/plot_result.py b/bench/plot_result.py
index 19f626e..653f52e 100755
--- a/bench/plot_result.py
+++ b/bench/plot_result.py
@@ -1,7 +1,7 @@
 #!/usr/bin/env python
 """Plot a result from benchmark.py
 
-Copyright (C) 2011-2020 - Daniele Varrazzo
+Copyright (C) 2011 - Daniele Varrazzo
 """
 import sys
 from collections import defaultdict
diff --git a/docs/Makefile b/docs/Makefile
index c09f452..b17d683 100644
--- a/docs/Makefile
+++ b/docs/Makefile
@@ -3,7 +3,7 @@
 # Use 'make env' once, then 'make html' to build the HTML documentation.
 # You can use PYTHON=python3.6 to use a different Python version to build.
 #
-# Copyright (C) 2011-2020 Daniele Varrazzo
+# Copyright (C) 2011 Daniele Varrazzo
 
 ENV_DIR = $(shell pwd)/env
 ENV_BIN = $(ENV_DIR)/bin
diff --git a/docs/conf.py b/docs/conf.py
index 3ddded3..64c596d 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -44,7 +44,7 @@
 
 # General information about the project.
 project = u'PostgreSQL Multiple Precision Arithmetic'
-copyright = u'2011-2020, Daniele Varrazzo'
+copyright = u'2011, Daniele Varrazzo'
 
 # The version info for the project you're documenting, acts as replacement for
 # |version| and |release|, also used in various other places throughout the
diff --git a/docs/lib/issue_role.py b/docs/lib/issue_role.py
index b8b0ae7..3974192 100644
--- a/docs/lib/issue_role.py
+++ b/docs/lib/issue_role.py
@@ -5,7 +5,7 @@
 
     An interpreted text role to link docs to issues.
 
-    :copyright: Copyright 2013-2020 by Daniele Varrazzo.
+    :copyright: Copyright 2013 by Daniele Varrazzo.
 """
 
 import re
diff --git a/sandbox/hello/hello.c b/sandbox/hello/hello.c
index 667490c..f0bbbf4 100644
--- a/sandbox/hello/hello.c
+++ b/sandbox/hello/hello.c
@@ -1,6 +1,6 @@
 /* A test program to study the mpz_t structure.
  *
- * Copyright (C) 2011-2020 Daniele Varrazzo
+ * Copyright (C) 2011 Daniele Varrazzo
  */
 
 #include <stdio.h>
diff --git a/sandbox/pi/calc_pi.py b/sandbox/pi/calc_pi.py
index 22de4dc..73979bd 100755
--- a/sandbox/pi/calc_pi.py
+++ b/sandbox/pi/calc_pi.py
@@ -2,7 +2,7 @@
 """
 A script to calculate pi using parallel PostgreSQL processes.
 
-Copyright (C) 2011-2020 Daniele Varrazzo
+Copyright (C) 2011 Daniele Varrazzo
 """
 
 import eventlet
diff --git a/sandbox/pi/calc_pi.sh b/sandbox/pi/calc_pi.sh
index 119664c..5771026 100755
--- a/sandbox/pi/calc_pi.sh
+++ b/sandbox/pi/calc_pi.sh
@@ -3,7 +3,7 @@
 # A script to calculate pi using parallel backends
 # See calc_pi.py for a more advanced version.
 #
-# Copyright (C) 2011-2020 Daniele Varrazzo
+# Copyright (C) 2011 Daniele Varrazzo
 
 export DBARGS=regression
 export NDIGITS=$1
diff --git a/sandbox/pi/pi.sql b/sandbox/pi/pi.sql
index 7e02d85..361550c 100644
--- a/sandbox/pi/pi.sql
+++ b/sandbox/pi/pi.sql
@@ -3,7 +3,7 @@
 -- Reference:
 -- https://web.archive.org/web/20111211140154/http://en.literateprograms.org/Pi_with_Machin's_formula_(Python)
 --
--- Copyright (C) 2011-2020 Daniele Varrazzo
+-- Copyright (C) 2011 Daniele Varrazzo
 
 CREATE FUNCTION arccot(x mpz, unity mpz) RETURNS mpz
     LANGUAGE plpgsql IMMUTABLE STRICT
diff --git a/sql/pgmp.pysql b/sql/pgmp.pysql
index 44160c4..37c9164 100644
--- a/sql/pgmp.pysql
+++ b/sql/pgmp.pysql
@@ -1,6 +1,6 @@
 /* pgmp -- Module installation SQL script
  *
- * Copyright (C) 2011-2020 Daniele Varrazzo
+ * Copyright (C) 2011 Daniele Varrazzo
  *
  * This file is part of the PostgreSQL GMP Module
  *
diff --git a/sql/uninstall_pgmp.sql b/sql/uninstall_pgmp.sql
index cdfc760..5ad30e5 100644
--- a/sql/uninstall_pgmp.sql
+++ b/sql/uninstall_pgmp.sql
@@ -1,6 +1,6 @@
 /* pgmp -- Module uninstall SQL script
  *
- * Copyright (C) 2011-2020 Daniele Varrazzo
+ * Copyright (C) 2011 Daniele Varrazzo
  *
  * This file is part of the PostgreSQL GMP Module
  *
diff --git a/src/pgmp-impl.h b/src/pgmp-impl.h
index c42df9a..82bfe44 100644
--- a/src/pgmp-impl.h
+++ b/src/pgmp-impl.h
@@ -1,6 +1,6 @@
 /* pgmp-impl -- Implementation details
  *
- * Copyright (C) 2011-2020 Daniele Varrazzo
+ * Copyright (C) 2011 Daniele Varrazzo
  *
  * This file is part of the PostgreSQL GMP Module
  *
diff --git a/src/pgmp.c b/src/pgmp.c
index f3fe860..a23f021 100644
--- a/src/pgmp.c
+++ b/src/pgmp.c
@@ -1,6 +1,6 @@
 /* pgmp -- PostgreSQL GMP module
  *
- * Copyright (C) 2011-2020 Daniele Varrazzo
+ * Copyright (C) 2011 Daniele Varrazzo
  *
  * This file is part of the PostgreSQL GMP Module
  *
diff --git a/src/pmpq.c b/src/pmpq.c
index 3110157..65f72ed 100644
--- a/src/pmpq.c
+++ b/src/pmpq.c
@@ -1,6 +1,6 @@
 /* pmpq -- PostgreSQL data type for GMP mpq
  *
- * Copyright (C) 2011-2020 Daniele Varrazzo
+ * Copyright (C) 2011 Daniele Varrazzo
  *
  * This file is part of the PostgreSQL GMP Module
  *
diff --git a/src/pmpq.h b/src/pmpq.h
index 2666df5..1045d2b 100644
--- a/src/pmpq.h
+++ b/src/pmpq.h
@@ -1,6 +1,6 @@
 /* pmpq -- PostgreSQL data type for GMP mpq
  *
- * Copyright (C) 2011-2020 Daniele Varrazzo
+ * Copyright (C) 2011 Daniele Varrazzo
  *
  * This file is part of the PostgreSQL GMP Module
  *
diff --git a/src/pmpq_agg.c b/src/pmpq_agg.c
index 2355595..beb65c1 100644
--- a/src/pmpq_agg.c
+++ b/src/pmpq_agg.c
@@ -1,6 +1,6 @@
 /* pmpq_agg -- mpq aggregation functions
  *
- * Copyright (C) 2011-2020 Daniele Varrazzo
+ * Copyright (C) 2011 Daniele Varrazzo
  *
  * This file is part of the PostgreSQL GMP Module
  *
diff --git a/src/pmpq_arith.c b/src/pmpq_arith.c
index 549cea6..bd66ad0 100644
--- a/src/pmpq_arith.c
+++ b/src/pmpq_arith.c
@@ -1,6 +1,6 @@
 /* pmpq_arith -- mpq arithmetic functions
  *
- * Copyright (C) 2011-2020 Daniele Varrazzo
+ * Copyright (C) 2011 Daniele Varrazzo
  *
  * This file is part of the PostgreSQL GMP Module
  *
diff --git a/src/pmpq_io.c b/src/pmpq_io.c
index aadb325..a6b1022 100644
--- a/src/pmpq_io.c
+++ b/src/pmpq_io.c
@@ -1,6 +1,6 @@
 /* pmpq_io -- mpq Input/Output functions
  *
- * Copyright (C) 2011-2020 Daniele Varrazzo
+ * Copyright (C) 2011 Daniele Varrazzo
  *
  * This file is part of the PostgreSQL GMP Module
  *
diff --git a/src/pmpz.c b/src/pmpz.c
index d4ab885..5002f5e 100644
--- a/src/pmpz.c
+++ b/src/pmpz.c
@@ -1,6 +1,6 @@
 /* pmpz -- PostgreSQL data type for GMP mpz
  *
- * Copyright (C) 2011-2020 Daniele Varrazzo
+ * Copyright (C) 2011 Daniele Varrazzo
  *
  * This file is part of the PostgreSQL GMP Module
  *
diff --git a/src/pmpz.h b/src/pmpz.h
index 85f0f6a..ca5d83d 100644
--- a/src/pmpz.h
+++ b/src/pmpz.h
@@ -1,6 +1,6 @@
 /* pmpz -- PostgreSQL data type for GMP mpz
  *
- * Copyright (C) 2011-2020 Daniele Varrazzo
+ * Copyright (C) 2011 Daniele Varrazzo
  *
  * This file is part of the PostgreSQL GMP Module
  *
diff --git a/src/pmpz_agg.c b/src/pmpz_agg.c
index e72c8c3..0d75287 100644
--- a/src/pmpz_agg.c
+++ b/src/pmpz_agg.c
@@ -1,6 +1,6 @@
 /* pmpz_agg -- mpz aggregation functions
  *
- * Copyright (C) 2011-2020 Daniele Varrazzo
+ * Copyright (C) 2011 Daniele Varrazzo
  *
  * This file is part of the PostgreSQL GMP Module
  *
diff --git a/src/pmpz_arith.c b/src/pmpz_arith.c
index a177b6c..569d112 100644
--- a/src/pmpz_arith.c
+++ b/src/pmpz_arith.c
@@ -1,6 +1,6 @@
 /* pmpz_arith -- mpz arithmetic functions
  *
- * Copyright (C) 2011-2020 Daniele Varrazzo
+ * Copyright (C) 2011 Daniele Varrazzo
  *
  * This file is part of the PostgreSQL GMP Module
  *
diff --git a/src/pmpz_bits.c b/src/pmpz_bits.c
index f20b5e1..58e820c 100644
--- a/src/pmpz_bits.c
+++ b/src/pmpz_bits.c
@@ -1,6 +1,6 @@
 /* pmpz_bits -- bit manipulation functions
  *
- * Copyright (C) 2011-2020 Daniele Varrazzo
+ * Copyright (C) 2011 Daniele Varrazzo
  *
  * This file is part of the PostgreSQL GMP Module
  *
diff --git a/src/pmpz_io.c b/src/pmpz_io.c
index 80b2b79..7ff14f5 100644
--- a/src/pmpz_io.c
+++ b/src/pmpz_io.c
@@ -1,6 +1,6 @@
 /* pmpz_io -- mpz Input/Output functions
  *
- * Copyright (C) 2011-2020 Daniele Varrazzo
+ * Copyright (C) 2011 Daniele Varrazzo
  *
  * This file is part of the PostgreSQL GMP Module
  *
diff --git a/src/pmpz_rand.c b/src/pmpz_rand.c
index 78548f3..2ca368d 100644
--- a/src/pmpz_rand.c
+++ b/src/pmpz_rand.c
@@ -1,6 +1,6 @@
 /* pmpz_rand -- mpz random numbers
  *
- * Copyright (C) 2011-2020 Daniele Varrazzo
+ * Copyright (C) 2011 Daniele Varrazzo
  *
  * This file is part of the PostgreSQL GMP Module
  *
diff --git a/src/pmpz_roots.c b/src/pmpz_roots.c
index 20ff6b7..a1cdb90 100644
--- a/src/pmpz_roots.c
+++ b/src/pmpz_roots.c
@@ -1,6 +1,6 @@
 /* pmpz_roots -- root extraction functions
  *
- * Copyright (C) 2011-2020 Daniele Varrazzo
+ * Copyright (C) 2011 Daniele Varrazzo
  *
  * This file is part of the PostgreSQL GMP Module
  *
diff --git a/src/pmpz_theor.c b/src/pmpz_theor.c
index 312da1e..a6d4f41 100644
--- a/src/pmpz_theor.c
+++ b/src/pmpz_theor.c
@@ -1,6 +1,6 @@
 /* pmpz_theor -- number theoretic functions
  *
- * Copyright (C) 2011-2020 Daniele Varrazzo
+ * Copyright (C) 2011 Daniele Varrazzo
  *
  * This file is part of the PostgreSQL GMP Module
  *
diff --git a/tools/sql2extension.py b/tools/sql2extension.py
index d5726c9..12566f2 100755
--- a/tools/sql2extension.py
+++ b/tools/sql2extension.py
@@ -8,7 +8,7 @@
 it doesn't know how to deal with.
 """
 
-# Copyright (c) 2011-2020, Daniele Varrazzo <daniele.varrazzo@gmail.com>
+# Copyright (c) 2011, Daniele Varrazzo <daniele.varrazzo@gmail.com>
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
diff --git a/tools/unmix.py b/tools/unmix.py
index b659165..431dd54 100755
--- a/tools/unmix.py
+++ b/tools/unmix.py
@@ -5,7 +5,7 @@
 ``!! PYON`` and ``!! PYOFF`` is executed and the output emitted.
 """
 
-# Copyright (c) 2011-2020, Daniele Varrazzo <daniele.varrazzo@gmail.com>
+# Copyright (c) 2011, Daniele Varrazzo <daniele.varrazzo@gmail.com>
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without