In case you want to download the complete thing:
wget -r -np -nH --cut-dirs=3 -R '.html,.tmp' https://people.inf.ethz.ch/wirth/ProjectOberon/index.html
wget -r -np -nH --cut-dirs=3 -R '.html,.tmp' https://people.inf.ethz.ch/wirth/ProjectOberon/index.html
Quick shell script v click a link.