Cited-by count in UNIXSD data May 9 - May 11

The cited-by count delivered in our UNIXSD data between May 9 - May 11 was incorrect because of a database issue. All cited-by counts were '0', this has been corrected. If you rely on this number and harvested data via OAI-PMH )or used our XML API) between May 9 - 11, please re-harvest.