Challenges  [electronic resource]. 

 - Basel :  MDPI AG 
 - Quarterly 
 - Began with vol. 1, issue 1 (Dec. 2010). 
<br/><br/> License restrictions may limit access. 
<br/><br/><label>ISSN: </label>2078-1547 
 = Challenges  (Basel) 
 = Challenges  (Basel) 
<br/><br/><label>LCCN: </label>2012261083 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Research and development projects--Periodicals.<br/>Research and development projects.
<br/><br/><label>Index Terms--Genre/Form: </label><br/>Electronic journals.
<br/><br/><label>LC Class. No.: </label>Q180.A1  / C53