add const variable to identify '**' (natural key identifier)
add const variable to identify '**' (natural key identifier)

uclouvain/OSIS-Louvain,uclouvain/osis,uclouvain/OSIS-Louvain,uclouvain/osis,uclouvain/OSIS-Louvain,uclouvain/osis,uclouvain/osis