Clearly marking retracted papers

[vanaukenk]

We should make certain that retracted papers are clearly marked as such in TPC, so curators don't mistakenly try to curate from them.
We do store the paper type 'Retracted publication' in postgres for C. elegans papers, but more generally, this should be available from the PubMed bibliography.
PubMed has also started making these retractions much clearer on their website:
http://www.ncbi.nlm.nih.gov/pubmed/22019085

[vanaukenk]

@goldturtle
I think we need to revisit this issue and make it a higher priority. There are papers currently being returned in the TPC searches that are retracted publications, but there's no indication of that in the returned paper display.
PMID:24049119 is an example. We have the information stored in postgres, or it should be readily available from PubMed.

[goldturtle]

transferred to TextpressoDevelopers/textpressocentral#22