many-to-many relationships doesn't even address OP's issue. What they want is the ability to have *repeated* option in the field. Say [Author A] [Author A] [Author A]. In many-to-many relationsips you still can't do that, for it allows multiple but still only distinct options in one field -- linking records like [Author A] [Author B] [Author C] is possible, but that suggested earlier is not.
I have a similar use case. My entries have some recursive/multi-layer characterstics, and I'm hoping to use multi-select to encode it, like: at the first layer, it has A property; on the second, it has B; on the third, well it can be A again. I wish to use a selectible field because the characteristics of the layers belong to a limited set, so it'd be a huge convenience to have them listed as dropdown options rather than entering them as plain text.
I suppose I could create a column for each layer, but I'm not really liking this solution as the number of layers in each entry is not a constant, nor is there really an upper bound to the number of layers permissible.
