Sometimes (8 from ~1200 papers), Scholar returns the results that look like `http://scholar.google.com/scholar?cluster=`. Right now, they are are skipped as not matching [papers.scholarURLPrefix](https://github.com/bzz/scholar-alert-digest/blob/bfb769eb3f3cf565e0c1dddf431de20caca9a2e6/papers/papers.go#L21).
Sometimes (8 from ~1200 papers), Scholar returns the results that look like
http://scholar.google.com/scholar?cluster=.Right now, they are are skipped as not matching papers.scholarURLPrefix.