Perhaps you should try some spelling variations:
collaborative series » collaborative services, collaborative studies, collaborative agencies
collaborative leader » collaborative teacher, collaborative leadership, collaborative learning
sweetland digital » stand digital
digital theorien » digital stories, digital rhetoric, digital terrain

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: sweetland digital theorien ((collaborative series) or (collaborative leader))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: sweetland digital theorien ((collaborative series) OR (collaborative leader)).
• Adding a wildcard symbol may retrieve word variants: sweetland digital theorien ((collaborative series) or (collaborative leader))*.