Note that the index numbers are only technical numbers which have no persistence. After a new system generation is done, all of them are invalid. To generate a persistent link, use the name.Use the URL:
http://ww-person.com/cgi-bin/l3/LANG=deu/F=Erard@I/N=de@Jaucourt@*@de@Jacourt,@d'Arsonval@et@d'Argancon
Erard I de Jaucourt * de Jacourt, d'Arsonval et d'Argancon
alternatively: /cgi-bin/llmult/LANG=germ/P=6040169