not all items have creators
not all items have creators

retorquere/zotero-better-bibtex,retorquere/zotero-better-bibtex,retorquere/zotero-better-bibtex,retorquere/zotero-better-bibtex,retorquere/zotero-better-bibtex,retorquere/zotero-better-bibtex