A method (502; 514; 530) is provided for managing, under the control of a computing
system, a plurality of ledgers (Lk). Each ledger comprises a corresponding persistent sequence of data blocks (DB), each ledger (Lk) being participated by a corresponding set of participant nodes (PNi) of the computing
system, the method comprising: —for at least one of said sets of participant nodes (PNi), said at least one participant node (PNi) of said set appends (512), to a ledger (Lk) corresponding to said set of participant nodes (PNi), at least one data block (DB) each one comprising a pointer (p(k′)) pointing to a different ledger (Lk′); —in response to a ledger relationship request by a requesting node (RE) about a selected ledger (Lk) and at least one selected pointer (p(k′)) comprised in the selected ledger (Lk), generating (518; 534) a graph structure (GS), comprising a set of graph nodes each one labelled with an identifier of a corresponding ledger (Lk), by: —adding a root
graph node labelled with an identifier of the selected ledger (Lk), and —performing a recursive procedure for an iterative pointer initialized to each of the selected pointers (p(k′)), the recursive procedure comprising: a) adding a child
graph node, labelled with an identifier of a ledger pointed by the iterative pointer, depending on a
graph node of the graph structure labelled with an identifier of the ledger comprising the iterative pointer, and b) iterating the recursive procedure for the iterative pointer set to each pointer of a set of the pointers comprised in the ledger pointed by the iterative pointer; —providing (520; 536) an indication of the generated graph structure to the requesting node (RE)—providing (520; 536) to the requesting node (RE) at least one of: —pointers (p(k′)) comprised in the ledgers (Lk) identified by identifiers
labelling the graph nodes of the graph structure (GS), and a proof that said pointers (p(k′)) have been included in data blocks (DB) of said ledgers.