context extractor crash

[wo]

2016-09-18 16:41:50 *** processing new link to http://link.springer.com/article/10.1007%2Fs11097-010-9165-z on http://perso.unifr.ch/fabian.dorsch/research.html ***
Traceback (most recent call last):
  File "bin/scraperdaemon.py", line 70, in <module>
    daemon.start()
  File "bin/scraperdaemon.py", line 38, in start
    self.run()
  File "bin/scraperdaemon.py", line 49, in run
    scraper.scrape(source)
  File "/home/wo/opp-tools/bin/../opp/scraper.py", line 139, in scrape
    process_link(li)
  File "/home/wo/opp-tools/bin/../opp/scraper.py", line 188, in process_link
    li.context = li.html_context()
  File "/home/wo/opp-tools/bin/../opp/models.py", line 260, in html_context
    l,r = par._outerHTML.split(el._outerHTML, 1)
ValueError: need more than 1 value to unpack