Definitions, descriptions and guiding texts to be shown in the VCR front-end application

 extensional:: Type of virtual collection that explicitly enumerates the references to resources or metadata documents that make up the collection
 intensional:: Type of virtual collection that defines a query by which the items of the collection can be retrieved ad-hoc from a secondary service (experimental, use at own risk!)

 purpose:: An indication of the intended usage of the present virtual collection
 research:: The virtual collection bundles resources that are relevant to a specific research (question).
 reference:: The virtual collection bundles resources, that are to be cited in a publication.
 sample:: This virtual collection bundles is intended to serve as an sample for research data
 future-use:: The purpose of this virtual collection is not specified yet. Used in published collection is advised against.
{{{#!comment
Original note by Oliver: ('''TBD:''' Actually, this is more a placeholder, e.g. people are unsure, what their VC may become. Before publishing, they should select one of the the above. Or, if required, we'll need to add more purposes).
See #607
}}}

 reproducibility:: An indication of the degree to which results obtained from processing of the present collection can be expected to be stable
 intended reproducibility:: Processing results can be expected to remain stable
 fluctuating reproducibility:: Processing results may vary
 untended reproducibility:: No claims with respect to the stability of the processing results are made
 reproducibility note:: Optional notes describing the expected reproducibility of processing results in more detail

 keyword:: A word or short phrase signifying a salient facet of the present virtual collection

 creators:: One or more persons, who created this virtual collection. \\ [Guidance note] Add a creator for each person involved in the creation of this virtual collection

 resources:: A persistent reference to the members that make up this virtual collection. These members may be of type ''metadata'' for referencing metadata or ''resource'' for directly referencing a resource. \\ [Guidance note] Click 'add' to add an individual reference of the type 'Metadata' or 'Resource' and optionally add a label and/or description. Click 'add more' to add multiple references (one per line) of one type without labels or resources. Individual resources can be edited at any stage.

The following are only relevant for ''intensional'' virtual collections
 [query] description:: A prose description of the procedure by which the collection items can be retrieved from the external service.
 [query] URI:: The location of the service from which the items should be retrieved. This value may be a persistent identifier, but could also be a plain URI although this is advised against for published collections.
{{{#!comment
Original note by Oliver:
('''TBD:''' Should this always be a PID, because URIs are not sustainable by definition?). Example: In case of FCS this could be the URI of an endpoint or a more enhanced aggregator.
See #607
}}}
 query profile:: Identifier of the mechanism, i.e. the protocol to be used, by which the members of the virtual collection should be retrieved. A application exploiting the query can use this to use a proper driver to talk to the service. Example: In case of CLARIN-FCS access the endpoint by FCS-compatible means.
 query value:: The query that should be passed on to the service by which it can look up the items that are part of this collection. This value should be in the query language supported by the service. Example: In case of CLARIN-FCS, this value is the CQL query to be send to the endpoint.