diff --git a/lua-physical_example.tex b/lua-physical_example.tex
index 14d6dbe..70c7291 100644
--- a/lua-physical_example.tex
+++ b/lua-physical_example.tex
@@ -1,6 +1,6 @@
 %!TEX program = lualatex
 
-% Copyright (c) 2020 Thomas Jenni
+% Copyright (c) 2021 Thomas Jenni
 
 % Permission is hereby granted, free of charge, to any person obtaining a copy
 % of this software and associated documentation files (the "Software"), to deal
diff --git a/src/physical-astronomical.lua b/src/physical-astronomical.lua
index 48ca564..629832b 100644
--- a/src/physical-astronomical.lua
+++ b/src/physical-astronomical.lua
@@ -1,7 +1,7 @@
 --[[
 Astronomical data
 
-Copyright (c) 2020 Thomas Jenni
+Copyright (c) 2021 Thomas Jenni
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
diff --git a/src/physical-data.lua b/src/physical-data.lua
index efc1a30..f77eee9 100644
--- a/src/physical-data.lua
+++ b/src/physical-data.lua
@@ -1,7 +1,7 @@
 --[[
 This file contains the methods for accessing physical data.
 
-Copyright (c) 2020 Thomas Jenni
+Copyright (c) 2021 Thomas Jenni
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
diff --git a/src/physical-definition.lua b/src/physical-definition.lua
index 958ece2..5e0ec79 100644
--- a/src/physical-definition.lua
+++ b/src/physical-definition.lua
@@ -2,7 +2,7 @@
 This file contains the definitions for dimensions, prefixes,
 SI, Imperial and U.S. Survey units
 
-Copyright (c) 2020 Thomas Jenni
+Copyright (c) 2021 Thomas Jenni
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
diff --git a/src/physical-dimension.lua b/src/physical-dimension.lua
index edd9e65..03cf315 100644
--- a/src/physical-dimension.lua
+++ b/src/physical-dimension.lua
@@ -3,7 +3,7 @@ The Dimension class keeps track of the dimenionality of a physical quantity.
 It can be used to perform validity checks on mathematical operations such as 
 addition and subtraction.
 
-Copyright (c) 2020 Thomas Jenni
+Copyright (c) 2021 Thomas Jenni
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
diff --git a/src/physical-number.lua b/src/physical-number.lua
index ecabfee..bd6a01e 100644
--- a/src/physical-number.lua
+++ b/src/physical-number.lua
@@ -2,7 +2,7 @@
 This file contains the number class which allows to do 
 calculations with uncertainties.
 
-Copyright (c) 2020 Thomas Jenni
+Copyright (c) 2021 Thomas Jenni
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
diff --git a/src/physical-quantity.lua b/src/physical-quantity.lua
index 54ebf7e..875a2ee 100644
--- a/src/physical-quantity.lua
+++ b/src/physical-quantity.lua
@@ -1,7 +1,7 @@
 --[[
 This file contains the quantity class
 
-Copyright (c) 2020 Thomas Jenni
+Copyright (c) 2021 Thomas Jenni
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
diff --git a/src/physical-unit.lua b/src/physical-unit.lua
index 65c0164..5c20722 100644
--- a/src/physical-unit.lua
+++ b/src/physical-unit.lua
@@ -2,7 +2,7 @@
 This file contains the unit class. It task is keeping 
 track of the unit terms.
 
-Copyright (c) 2020 Thomas Jenni
+Copyright (c) 2021 Thomas Jenni
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
diff --git a/src/physical.lua b/src/physical.lua
index 7fef075..6964687 100755
--- a/src/physical.lua
+++ b/src/physical.lua
@@ -3,8 +3,8 @@
 lua-physical
 
 Author: Thomas Jenni 
-Version: 1.0.4
-Date: 2020-09-15
+Version: 1.0.5
+Date: 2021-05-08
 
 License: MIT
 
@@ -31,16 +31,14 @@ SOFTWARE.
 
 -- Source: http://kiki.to/blog/2014/04/12/rule-5-beware-of-multiple-files/
 
-local prefix = ''
+local Dimension = require('physical-dimension')
+local Unit = require('physical-unit')
+local Quantity = require('physical-quantity')
+local Number = require('physical-number')
 
-local Dimension = require(prefix..'physical-dimension')
-local Unit = require(prefix..'physical-unit')
-local Quantity = require(prefix..'physical-quantity')
-local Number = require(prefix..'physical-number')
+require('physical-definition')
 
-require(prefix..'physical-definition')
-
-local Data = require(prefix..'physical-data')
+local Data = require('physical-data')
 
 local m = {
 	Dimension = Dimension,