In a complex system many subsystems can be distinguished; and since many complex systems are hierarchic, each subsystem is nested in a larger subsystem etc.
The chief argument in favour of the network model, in comparison to the hierarchic model, was that it allowed a more natural modeling of relationships between entities.
Following the 1968 movement labour and the forms of collaboration among the librarians became less hierarchic, more collegial and broader as to the number of personnel included in decision taking.