Our site uses a system of tags (a taxonomy) to categorize material. The valid tags are the titles of VN works as well as general topics such as "women" or "Nabokov friends". It's easy to get a list of pages marked by a certain tag.
Unfortunately someone editing the bibliography created a lot of wrong tags which are complete bibliographic entries. These tags are empty (i.e. no pages marked by them) and need to be deleted from the taxonomy to avoid messing it up. Please go to https://thenabokovian.org/admin/structure/taxonomy/manage/tags/overview and clean it up, for example
is a valid tag and should remain, but
is an error and should be deleted from the tag list. If you want to do this but have no rights to access that page, let me know and I will upgrade you :)