Books page: Update additional information URL

Author: SableRaf

content/books/creating-procedural-artworks/index.mdx

@@ -11,6 +11,4 @@ This book started as a set of tutorials for university level multimedia students
 
 The chapters are organised to weave together programming functionality and design principles presenting one concept at a time, with multiple hands on exercises in each chapter.
 
-Additional information available at http://holistic3d.com/creating-procedural-artworks/
-
-Experience an example of the artworks created at http://holistic3d.com/processing
+Additional information available at https://processing.holistic3d.com/