Here is a simple [[/script/bibclean-v1|script]] that can help you clean your bibliography file. Have you encountered the following situation? After executing //bibtex// command, you find the following item in your bbl file. {{{ \bibitem[BGS07]{BS07} S.~Benzoni-Gavage and D.~Serre, \emph{Multi-dimensional {H}yperbolic {P}artial {D}ifferential {E}quations}, Oxford University Press, 2007. \bibitem[Br{\'e}73]{Bre73} H.~Br{\'e}zis, \emph{Op\'erateurs maximaux monotones et semi-groupes de contractions dans les espaces de {H}ilbert}, North-Holland Publishing Co., Amsterdam, 1973, North-Holland Mathematics Studies, No. 5. Notas de Matem{\'a}tica (50). }}} Notice that **BS07** and **Bre73** are your (defined by yourself) citation keys, sometimes it seems **BGS07** and **Br{\'e}73** is your citation keys automatically generated by //bibtex//. I would like to replace the generated citation keys by my own citation keys, and here is my [[/script/bibclean-v1|solution]].