ID of a list which the current list continues; used to connect discontiguous lists that form one logical list.
Sometimes a list may be interrupted by other material that is not part of the list. In that case, the list should be marked up as two (or more) lists, and each one except the first should use this attribute to refer to the ID of the preceding one. This connection allows processors to treat the parts as parts of a larger logical list, for example, by numbering items consecutively rather than restarting each (partial) list at 1.
This attribute should refer to an ID on the same type of element as it occurs on.