The following is from a discussion paper [1] being presented at the MARC 
Advisory Committee at ALA. It has information about BIBFRAME treatment 
of relators (MARC relators [2] and RDA/FRBR entity relationships [3]) 
that I have not yet seen on the BIBFRAME site, so I thought it might be 
of interest:

> In BIBFRAME these relationships are handled as follows.  The 
> illustrations shown below use the RDF turtle notation. (See 
> Introduction to Turtle used in MAC Papers 
> <>.)
> In the BIBFRAME vocabulary the relationships between cataloging 
> resources and between cataloging resources and names (commonly called 
> roles or relators) such as those in Appendices J and I respectively 
> are accommodated by sets of properties with the "escape" to designate 
> any relationship not specifically provided.  This provides flexibility 
> and encourages efficiency in expressing the relationships via URIs for 
> the descriptions of the related resources where possible.
> For the cataloging resource relationships the set goes from the most 
> general, relatedResource, to the general (which are essentially the 
> high level relationship categories in the RDA Appendix J (e.g., 
> equivalent, accompanies, precedes, etc.) to a number of specific 
> relationships (series, translation, dataSource, supplement, etc.).  
> The latter includes the specific supersedes and precedes sub 
> relationships used by the ISSN system.  Not all of the 300+ and their 
> reciprocals are expressed as properties.  All of the included 
> properties efficiently link directly to the URI of the description of 
> the related resource. If a more specific relationship is needed, then 
> the relationship can be expressed in URI or literal form, and the link 
> to the description of the related resource can be specified via the 
> Related class.
> work1  a  bf:Work;
>             bf:accompanies  <work2 URI>.
> work1 a bf:Work
>             bf:accompanies   relationship1.
> relationship1  a  bf:Related;
>             bf:relationship  "augmented by catalogue";
>             bf:identifier  <work2 URI>.
> The relationships between cataloging resources and names as RDA list 
> in Appendix J and the one aligned with it in MARC that also provides 
> codes are similarly expressed as properties with a very general 
> property relatedAgent and three general properties, agent, creator, 
> and contributor, with additional relationships expressed in literal or 
> URI form as above.
> work1  a  bf:Work;
>             bf:contributor  <URI for illustrator's name>.
> work1 a bf:Work
>             bf:contributor   relationship1.
> relationship1  a  bf:Related;
>             bf:relationshipID;
>             bf:identifier  <URI for illustrator's name>.
I'm assuming that the "relationship1" in these examples is a blank node, 
although it isn't indicated as such. I'm not clear on how one knows the 
nature of the value of bf:identifier, particularly when the relationship 
is a literal string. Perhaps I'm overlooking something?


[3] Not having access to the RDA toolkit, I guess the best other source 
for these is the registry recently announced:

Karen Coyle
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