If bf:electronicLocator must expect a literal, then the current proposal is better than your suggested alternative: less complex. Concerning a reciprocal link, I think it will be useful to have in the model. You are right that in general an Instance will not know about all Items related to it, but in specific local implementations it will be more efficient to link to known Items. The model should at least provide that possibility. Joe From: Bibliographic Framework Transition Initiative Forum [mailto:[log in to unmask]] On Behalf Of Denenberg, Ray Sent: Thursday, November 12, 2015 12:06 PM To: [log in to unmask] Subject: Re: [BIBFRAME] Properties of Item proposal Hi Joseph - thanks for the comments and questions. I want to address two points, while we are still discussing the other suggestions. bf:electronicLocator is, at present, conceived to be a datatype property; its expected value is a literal. We could change that to an object property if that's what people want, however, the URI would still be a literal, because it is not an RDF resource. In the example, the electronic locator is http://hdl.loc.gov/loc.pnp/cph.3g11323 and this is not an RDF resource. (By RDF resource, we mean, you can dereference the URI and get RDF in response. You can't for this URI.) If bf:electronicLocator were to be redefined as an object property, then instead of this: <http://bibframe.example.org/item/item5> a bf:Item ; bf:electronicLocator "http://hdl.loc.gov/loc.pnp/cph.3g11323" ; ...... It might look like this: <http://bibframe.example.org/item/item5> a bf:Item ; bf:electronicLocator [ a bf:ElectronicLocator ; rdf:value "http://hdl.loc.gov/loc.pnp/cph.3g11323" ] ; ...... Where here we now have defined class bf:ElectronicLocator, but the URI is still a literal. Second, should bf:itemOf (property of item) have a reciprocal property, bf:hasItem (property of Instance). I don't know; opinions are welcomed on this question. We did not include it in the draft for this reason: an item knows (or should know) what Instance it is an Item of. An Instance in general does not know the existence of all items that claim to be an item of that Instance. So if there were to be a property bf:hasItem, it could be used within an Instance to point to all items that that Instance knows about with the disclaimer that it doesn't claim to point to all its items. If, as such, this would be useful then we can add the property. (The same dilemma applies to instanceOf and hasInstance. And granted, these are both included in BIBFRAME 1.0.) Ray From: Bibliographic Framework Transition Initiative Forum [mailto:[log in to unmask]] On Behalf Of Joseph Kiegel Sent: Tuesday, November 10, 2015 1:39 PM To: [log in to unmask]<mailto:[log in to unmask]> Subject: [BIBFRAME] Properties of Item proposal Items in BIBFRAME may serve different purposes, which is not addressed in the Items proposal. A relatively narrow purpose is to support the user task obtain, while a more complex one is to support a working circulation system. The properties elaborated in the proposal are not sufficient even for the user task obtain. Here are comments on them. bf:electronicLocator: should the expected value be a URI? It seems odd to express URLs as literals in linked data. bf:heldBy and bf:subLocation: the MARC holdings format and many library systems recognize three levels of location information: organization, library and sublocation within a library. BIBFRAME should support the same number of levels: for example, it should add a property such as bf:location, which is intermediate between bf:heldBy and bf:subLocation. bf:heldBy University of Washington Libraries bf:location: Art Library bf:subLocation: Reference stacks bf:heldBy University of Washington Libraries bf:location: Engineering Library bf:subLocation: Reference stacks Without bf:location, reference or general stacks locations in different buildings appear to be the same. bf:itemOf: is a reciprocal property needed? For example, bf:hasItem, a property of bf:Instance with an expected value of bf:Item. Two properties are lacking from the proposal: bf:itemStatus and bf:circulationCharacteristic bf:itemStatus: it is crucial to inform users of the status of an item, e.g. available, checked out, missing, withdrawn, at the bindery, etc. bf:circulationCharacteristic: another important aspect of materials is the general policy that governs them, e.g. circulating or library use only. It is tempting to try to include this characteristic in bf:itemStatus, but they are independent aspects. LUO materials may be missing, at the bindery or even checked out (e.g. faculty loans of reference materials).