diff --git a/README.txt b/README.txt
index 097d6d2ac30ef86067fe6c12579f1997d26a328f..875edd596fc7fd3cff471c6b945ad9b74e0eedd6 100644
--- a/README.txt
+++ b/README.txt
@@ -9,24 +9,24 @@ Source changes are maintained in version control and bug tracking is online.
 Online Links
  [1] https://savage.nps.edu/Savage
  [2] https://savage.nps.edu/X3dExamplesSavage.zip
- [3] http://www.web3d.org/x3d/content/examples/X3dResources.html#Savage
+ [3] https://www.web3d.org/x3d/content/examples/X3dResources.html#Savage
  [4] https://savage.nps.edu/Savage/license.html
- [5] http://www.web3d.org/x3d/content/examples (redirects to)
-     http://www.web3d.org/x3d/content/examples/X3dResources.html#Examples
+ [5] https://www.web3d.org/x3d/content/examples (redirects to)
+     https://www.web3d.org/x3d/content/examples/X3dResources.html#Examples
 
 Additional References
- [6] http://x3dgraphics.com
- [7] http://x3dgraphics.com/slidesets
+ [6] https://x3dgraphics.com
+ [7] https://x3dgraphics.com/slidesets
  [8] https://savage.nps.edu/X3D-Edit
  [9] https://savage.nps.edu/X3dValidator
-[10] http://www.web3d.org/x3d/content/examples (redirects to)
-     http://www.web3d.org/x3d/content/examples/X3dResources.html
-[11] http://www.web3d.org/x3d/content/examples/X3dResources.html#Tooltips
-[12] http://www.web3d.org/x3d/content/examples/X3dSceneAuthoringHints.html
+[10] https://www.web3d.org/x3d/content/examples (redirects to)
+     https://www.web3d.org/x3d/content/examples/X3dResources.html
+[11] https://www.web3d.org/x3d/content/examples/X3dResources.html#Tooltips
+[12] https://www.web3d.org/x3d/content/examples/X3dSceneAuthoringHints.html
 [13] https://www.movesinstitute.org/Video/Courses/X3dForWebAuthors/X3dForWebAuthorsVideo.html
 [14] https://savage.nps.edu/Savage/developers.html
-[15] http://www.web3d.org/specifications
-[16] http://www.web3d.org/standards
+[15] https://www.web3d.org/specifications
+[16] https://www.web3d.org/standards
 
 Build scripts are written using Ant with build.xml found in the archive's root.
 [17] https://savage.nps.edu/Savage/build.xml