# Parallel cites

**URL:** <https://discourse.citationstyles.org/t/parallel-cites/802>\
**Category:** CSL Development\
**Created:** [December 13, 2009, 10:34pm UTC](https://discourse.citationstyles.org/t/parallel-cites/802 "2009-12-13T22:34:51Z")\
**Posts on this page:** 8\
**Page:** 1

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**Author:** ![Frank\_Bennett](https://yyz1.discourse-cdn.com/flex029/user_avatar/discourse.citationstyles.org/frank_bennett/32/198_2.png) [@Frank\_Bennett](https://discourse.citationstyles.org/u/Frank_Bennett)\
**Post date:** [December 13, 2009, 10:34pm UTC](https://discourse.citationstyles.org/t/parallel-cites/802/1 "2009-12-13T22:34:51Z")

</div>

Parallel citation is a show-stopper issue for law that I have so far  
shoved aside in the work on citeproc-js. It is required by most legal  
citation styles for law cases, legislation and treaties, and look like  
this:

Chaoulli v. Quebec (Attorney General), 2005 SCC 35, [2005] 1 S.C.R. 791.  
Green v. State, 334 Ark. 484, 978 S.W.2d 300 (1998).

I’ve been assuming that this will need to be handled somehow through  
the “fabled” hierarchical data model, but I’m now playing with the  
idea that, in the short term at least, it can be done in the processor  
as a special case of collapsing behavior. That is, users would have  
two entries for each of the cases above in their database, and when  
they are inserted into a citation in sequence, they can be collapsed  
into the form shown above. As far as I can tell, there are just two  
cases that such simple output collapsing would not handle correctly.  
One is “ibid” backreferencing:

1. Green v. State, 334 Ark. 484, 978 S.W.2d 300 (1998).
2. Id. at 485, 978 S.W.2d at 301.

This would not work. The cite to S.W.2d would be seen as the  
immediately preceding cite, causing the Id. backreference to fail. In  
the absence of some sort of workaround in the position machinery, you  
would get something like this instead:

1. Green v. State, 334 Ark. 484, 978 S.W.2d 300 (1998).
2. Green, 334 Ark. at 485, 978 S.W.2d at 301.

The user would need to manually change the first reference in cite (2)  
to “Id. at 485”. I’m thinking that this is preferable to the current  
situation, where the output would look like this:

1. Green v. State, 334 Ark. 484 (1998), Green v. State, 978 S.W.2d 300 (1998).
2. Green, 334 Ark. at 485, Green, 978 S.W.2d at 301.

The second place where this would break is in bibliographies; until  
relations support comes down the pike, these would produce a separate  
entry for each of the items.

With this interim approach, collapsing would only occur where the  
rendered cites in a sequence differ only in their volume,  
container-title, page and locator. As far as I can tell, this would  
be safe to impose generally, without the need for a controlling option  
in CSL. It’s only a provisional solution, but the intention is to at  
least get us off the ground for legal support, without complicating  
things for other, better solutions down the road.

Thoughts and reactions? Andreas?

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<div class="post-metadata">

**Author:** ![Bruce\_D\_Arcus1](https://avatars.discourse-cdn.com/v4/letter/b/4bbf92/32.png) [@Bruce\_D\_Arcus1](https://discourse.citationstyles.org/u/Bruce_D_Arcus1)\
**Post date:** [December 14, 2009, 12:00am UTC](https://discourse.citationstyles.org/t/parallel-cites/802/2 "2009-12-14T00:00:18Z")

</div>

…

Before we get farther into this, can you please stop and explain the  
above to the legal laypeople here? Are these two separate legal  
opinions, each published in more than one place, so that you only  
needed to include one to illustrate the point? Or something else?

Bruce

---

<div class="post-metadata">

**Author:** ![Frank\_Bennett](https://yyz1.discourse-cdn.com/flex029/user_avatar/discourse.citationstyles.org/frank_bennett/32/198_2.png) [@Frank\_Bennett](https://discourse.citationstyles.org/u/Frank_Bennett)\
**Post date:** [December 14, 2009, 2:14am UTC](https://discourse.citationstyles.org/t/parallel-cites/802/3 "2009-12-14T02:14:31Z")

</div>

> > Parallel citation is a show-stopper issue for law that I have so far  
> > shoved aside in the work on citeproc-js. It is required by most legal  
> > citation styles for law cases, legislation and treaties, and look like  
> > this:
> > 
> > Chaoulli v. Quebec (Attorney General), 2005 SCC 35, [2005] 1 S.C.R. 791.  
> > Green v. State, 334 Ark. 484, 978 S.W.2d 300 (1998).
> 
> Before we get farther into this, can you please stop and explain the  
> above to the legal laypeople here? Are these two separate legal  
> opinions, each published in more than one place, so that you only  
> needed to include one to illustrate the point? Or something else?

Quite right. Court judgements, legislation and international  
agreements are often published in multiple reporters. The same text  
will be contained in each reporter, the only difference being the  
pagination (or other locator information). Courts and law reviews  
often require that several commonly available reporters be cited for a  
single judgement, as a convenience to readers who have access to only  
one of the reporters in which the text appears.

This is a different problem from properly hierarchical relations such  
as cites to appeals judgements or amending legislation, although it is  
somewhat related in the implementation.

Parallel citation is a pain, but it’s extremely important in the  
trade. There’s even a lawsuit that turns on it, the (non-parallel)  
citation for which is: West Pub. Co. v. Mead Data Cent., Inc., 616 F.  
Supp. 1571 (D. Minn. 1985), aff’d, 799 F.2d 1219 (8th Cir.), cert.  
denied, 479 U.S. 1070 (1986).

---

<div class="post-metadata">

**Author:** ![Bruce\_D\_Arcus1](https://avatars.discourse-cdn.com/v4/letter/b/4bbf92/32.png) [@Bruce\_D\_Arcus1](https://discourse.citationstyles.org/u/Bruce_D_Arcus1)\
**Post date:** [December 14, 2009, 2:45am UTC](https://discourse.citationstyles.org/t/parallel-cites/802/4 "2009-12-14T02:45:03Z")

</div>

I have a feeling this is going to be a problem that’s going to get  
solved slowly, with some pain.

The data modeling could actually be a major PITA for BIBO RDF, as well  
as for how we’ve previously discussed the new model in Zotero.

Bruce

---

<div class="post-metadata">

**Author:** ![Frank\_Bennett](https://yyz1.discourse-cdn.com/flex029/user_avatar/discourse.citationstyles.org/frank_bennett/32/198_2.png) [@Frank\_Bennett](https://discourse.citationstyles.org/u/Frank_Bennett)\
**Post date:** [December 14, 2009, 12:38pm UTC](https://discourse.citationstyles.org/t/parallel-cites/802/5 "2009-12-14T12:38:53Z")

</div>

> > > > Parallel citation is a show-stopper issue for law that I have so far  
> > > > shoved aside in the work on citeproc-js. It is required by most legal  
> > > > citation styles for law cases, legislation and treaties, and look like  
> > > > this:
> > > > 
> > > > Chaoulli v. Quebec (Attorney General), 2005 SCC 35, [2005] 1 S.C.R. 791.  
> > > > Green v. State, 334 Ark. 484, 978 S.W.2d 300 (1998).
> > > 
> > > Before we get farther into this, can you please stop and explain the  
> > > above to the legal laypeople here? Are these two separate legal  
> > > opinions, each published in more than one place, so that you only  
> > > needed to include one to illustrate the point? Or something else?
> > 
> > Quite right. Court judgements, legislation and international  
> > agreements are often published in multiple reporters. The same text  
> > will be contained in each reporter, the only difference being the  
> > pagination (or other locator information). Courts and law reviews  
> > often require that several commonly available reporters be cited for a  
> > single judgement, as a convenience to readers who have access to only  
> > one of the reporters in which the text appears.
> > 
> > This is a different problem from properly hierarchical relations such  
> > as cites to appeals judgements or amending legislation, although it is  
> > somewhat related in the implementation.
> 
> I have a feeling this is going to be a problem that’s going to get  
> solved slowly, with some pain.
> 
> The data modeling could actually be a major PITA for BIBO RDF, as well  
> as for how we’ve previously discussed the new model in Zotero.

I’ll reveal my ignorance by asking, but does this need to be reflected  
in BIBO? The relation of the entries can be deduced from their field  
content, and if it’s just a matter of output formatting, that can be  
handled reliably and fairly simply in the implementation.

I’m not sure how relevant the relationship would be to data exchange,  
since the “parallel” items do refer to different documents: even  
though the bulk of their content consists of identical text, they  
differ in pagination, and in some publisher-supplied metadata such as  
commentary and other annotations.

Frank

---

<div class="post-metadata">

**Author:** ![Bruce\_D\_Arcus1](https://avatars.discourse-cdn.com/v4/letter/b/4bbf92/32.png) [@Bruce\_D\_Arcus1](https://discourse.citationstyles.org/u/Bruce_D_Arcus1)\
**Post date:** [December 14, 2009, 2:34pm UTC](https://discourse.citationstyles.org/t/parallel-cites/802/6 "2009-12-14T14:34:16Z")

</div>

> I’ll reveal my ignorance by asking, but does this need to be reflected  
> in BIBO? The relation of the entries can be deduced from their field  
> content, and if it’s just a matter of output formatting, that can be  
> handled reliably and fairly simply in the implementation.

I don’t understand you above. What “field content”? And “it’s just a  
matter …” for what agent?

> I’m not sure how relevant the relationship would be to data exchange,  
> since the “parallel” items do refer to different documents: even  
> though the bulk of their content consists of identical text, they  
> differ in pagination, and in some publisher-supplied metadata such as  
> commentary and other annotations.

So then how do you store all this in the database, and represent it in the RDF?

Bruce

---

<div class="post-metadata">

**Author:** ![Frank\_Bennett](https://yyz1.discourse-cdn.com/flex029/user_avatar/discourse.citationstyles.org/frank_bennett/32/198_2.png) [@Frank\_Bennett](https://discourse.citationstyles.org/u/Frank_Bennett)\
**Post date:** [December 14, 2009, 9:13pm UTC](https://discourse.citationstyles.org/t/parallel-cites/802/7 "2009-12-14T21:13:31Z")

</div>

> > I’ll reveal my ignorance by asking, but does this need to be reflected  
> > in BIBO? The relation of the entries can be deduced from their field  
> > content, and if it’s just a matter of output formatting, that can be  
> > handled reliably and fairly simply in the implementation.
> 
> I don’t understand you above. What “field content”? And “it’s just a  
> matter …” for what agent?

I should have said “variable content”, the agent being the CSL processor.

> > I’m not sure how relevant the relationship would be to data exchange,  
> > since the “parallel” items do refer to different documents: even  
> > though the bulk of their content consists of identical text, they  
> > differ in pagination, and in some publisher-supplied metadata such as  
> > commentary and other annotations.
> 
> So then how do you store all this in the database, and represent it in the RDF?

I think I’m suggesting that it may be sufficient to describe the items  
individually. In CSL output, we collapse to (Smith 1990a, 1990b) on  
the basis of variable content seen by the processor. I’m wondering  
whether parallel cites are closer to that case than to hierarchical  
items like a translation, a republication or an appellate judgement.

---

<div class="post-metadata">

**Author:** ![Frank\_Bennett](https://yyz1.discourse-cdn.com/flex029/user_avatar/discourse.citationstyles.org/frank_bennett/32/198_2.png) [@Frank\_Bennett](https://discourse.citationstyles.org/u/Frank_Bennett)\
**Post date:** [December 19, 2009, 9:36am UTC](https://discourse.citationstyles.org/t/parallel-cites/802/8 "2009-12-19T09:36:01Z")

</div>

> > > I’ll reveal my ignorance by asking, but does this need to be reflected  
> > > in BIBO? The relation of the entries can be deduced from their field  
> > > content, and if it’s just a matter of output formatting, that can be  
> > > handled reliably and fairly simply in the implementation.
> > 
> > I don’t understand you above. What “field content”? And “it’s just a  
> > matter …” for what agent?
> 
> I should have said “variable content”, the agent being the CSL processor.
> 
> > > I’m not sure how relevant the relationship would be to data exchange,  
> > > since the “parallel” items do refer to different documents: even  
> > > though the bulk of their content consists of identical text, they  
> > > differ in pagination, and in some publisher-supplied metadata such as  
> > > commentary and other annotations.
> > 
> > So then how do you store all this in the database, and represent it in the RDF?
> 
> I think I’m suggesting that it may be sufficient to describe the items  
> individually. In CSL output, we collapse to (Smith 1990a, 1990b) on  
> the basis of variable content seen by the processor. I’m wondering  
> whether parallel cites are closer to that case than to hierarchical  
> items like a translation, a republication or an appellate judgement.

Further to this item, I have some parallel cite detection code brewing  
in citeproc-js that will be able to reliably format parallel cites as  
used in legal styles. Working up the code has convinced me that this  
really can and should be treated more as a matter of output formatting  
than of relationships within the underlying data.

Cites that collapse in this way have to have a fairly narrow set of  
visual characteristics if the collapsed form is going to make any  
sense, so even if two items were flagged as “siblings” in the  
database, we can’t really take that on faith; elaborate validation is  
still required, in the processor, to determine whether it is safe to  
collapse them. Because the formatting constraints are tight, the  
result of parallel-collapsing-is-okay validation can be taken as a  
reliable proxy for a these-items-are-siblings hint in the data. We  
don’t really need such a hint, and if it were available, it wouldn’t  
gain us anything.

I know that may sound cryptic, but I’ll leave it there for now. The  
main thing is that I’ve figured out how to handle the use case for  
citation purposes, and there is no immediate or pressing need to worry  
about how to describe parallel or sibling items in RDF, or to flag  
them in the database. All’s well.

Frank