January 18, 2016
Thanks -- how well do you understand composite styles? That's currently the key skill we'd required: someone who has a good sense of how Zotero citations currently work and is able to work&think through with us how that could be translate into citation styles. The actual syntax (which doesn't currently exist in CSL) is secondary once we've figured out what programmers would call the pseudo-code.
The first things I'm wondering about is, do you ever get something like 1,2 in composite styles or are citations always grouped when first cited?
Next, how about subsequent citations -- if I cite one part of a composite reference that's 2b, correct? Even when I combine it with a new set of references? I.e. I'd get 2b, 3 (where 3 would then consider a new a,b,c)?
Are whole composite references repeated? I.e. would I cite 2 again in a document to refer to the same group? How would I enter this on the reference manager side -- just the same bunch of references or should/need there by some way to select a whole previously cited group? If the first, presumably order doesn't matter?
fbennett has thought most about this, he may have more questions.
January 18, 2016
Well, I have done my best to avoid composite references in the past - quite successfully I'd say ;-)
What you describe is my understanding at the moment, but I need to study the relevant parts of the ACS Style Guide and Wiley-VCH guidelines to check for possible tricks. I hope I can give you a more solid answer later this week.
January 18, 2016
edited January 18, 2016
says, the primary issue to solve first is determining the exact mechanics of these type of styles, and to get a feel about the amount of flexibility that is needed in terms of Citation Style Language features and (Zotero) UI support.
At some point we would have to make some changes to CSL so that styles can express those requirements, and the CSL processors would have to be modified to be able to deal with those changes. But that's really a later concern.
E.g., in addition to the questions
already raised, are there any styles that use roman numerals instead of Latin letters for the subindices (e.g. "1. i) ..., ii) ..., etc.")? Do all composite styles sort the citation-numbers in citations, or is it possible to have "(3, 2b, 6c)" instead of "(2b, 3, 6c)"? Is it common to have descriptions in bibliographic entries? E.g.,
gives as example " A. Kraft, Chem. Commun. 1996, 77, and references therein; Sci. Am. 1984, 250(4), 7; B. Krebs, H. U. Hürter, Acta Crystallogr. Sect. A 1981, 37, 163; G. Eulenberger, Z. Naturforsch. B 1981, 36, 521; D. Bruss, Appl. Phys. B, DOI 10.1007/s003409900185.". I'm not even sure what's going on here, since no subindices are used in this example.
January 18, 2016
In answer to your questions:
Q1. "The first things I'm wondering about is, do you ever get something like 1,2 in composite styles or are citations always grouped when first cited?"
A1. You can have either. Endnote always groups adjacent refs together, but there are workarounds for this.
Q2. Next, how about subsequent citations -- if I cite one part of a composite reference that's 2b, correct? Even when I combine it with a new set of references? I.e. I'd get 2b, 3 (where 3 would then consider a new a,b,c)?
Q3. Are whole composite references repeated? I.e. would I cite 2 again in a document to refer to the same group?
Q4. How would I enter this on the reference manager side -- just the same bunch of references or should/need there by some way to select a whole previously cited group? If the first, presumably order doesn't matter?
A4. As you write, you just use the ref you need. If the software recognizes that ref as being, for example, 2b in some text above, then it will say 2b in the new instance. Same goes for multiple refs.
For example, imagine on page 1 I write:
Jack and Jill went up the hill.
where  is a composite reference involving a)..., b)..., c)..., d)...
If in a later section I write:
Hills are difficult to climb.
and I want to use all four references that were previously 1a, 1b, 1c and 1d, the sentence will appear as:
Hills are difficult to climb.
If I used only what was 1b and 1c, it will come out as:
Hills are difficult to climb.[1b,c]
If I use 1b, 1c and 1d, you should be able to choose how it comes out, but most often you want a range then (because listing all the refs becomes ugly):
Hills are difficult to climb.[1b-d]
Finally, I might want that and another previously unused reference (or used elsewhere):
Hills are difficult to climb.[1b-d, 7]
Or even parts of a different group, eg:
Hills are difficult to climb.[1b-d, 7a,b]
And so on.
The crucial part of this is for the ref manager to recognise whether a particular ref was used already previously in the text and simply use its number again. Then, to group them neatly into a sequence or range.
You should be able to edit each range, and which reference is a) and which one is b) and which one is c) inside a particular group.
A further consideration, which was brought up above:
The exact nomenclature should be flexible. It's not always lowercase letters. You might have:
1a, 1b, 1c... all part of 1.
or you might have Roman numerals:
1i, 1ii, 1iii all part of 1.
Or you might use
Ai, Aii, Aiii, Aiv...
Endnote offers such flexibility, so you can choose, for example which style you use, how many references are needed before it is reported as a range and so on. There are fields where you choose how things are numbered. EndNote seems to understand this is simply sequences and part of sequences we are dealing with so I guess it doesn't care which precise nomenclature is used. It does the same job for all of them.
January 18, 2016
Q1. "Do all composite styles sort the citation-numbers in citations, or is it possible to have "(3, 2b, 6c)" instead of "(2b, 3, 6c)"? "
A1. Don't know about all journals. I've never seen it not ordered. Might want to provide the option. It's possible this option exists in EndNote, but without needing it I never looked. It's also very easy to workaround if it can't be done but was needed. On the flipside of that coin, I've seen plenty of draft manuscripts, grant proposals in which disordered refs (e.g. [3, 2b, 6c]) were spotted as a "mistake" to be corrected.
Q2. Is it common to have descriptions in bibliographic entries?
A2. Yes. Very common.
For example "and references therein." as you wrote above. But also something like:
 For studies using Pd catalysts, see: a) ..., b).... ; For references using Rh catalysts, see: c)..., d)..., e)... . For recent reviews see: f)..., g)... .
Endnote is weak on this. However, you can add such descriptions easily after your finished writing everything else by converting the entire set of Endnote fields to plain text, then adding in the comments as above. Although it would be nice to have field in each reference in the libarary where you could put text that gets put before the letter for that reference.
January 19, 2016
I didn't agree with lavoisier regarding the frequency of descriptions in bibliographic entries, so I have collected some numbers.
In the latest issue of the Journal of the American Chemical Society (2016, Volume 138, Issue 1), out of 63 articles, 19 use descriptions in at least one entry of the bibliography. I admit this is more frequent than I thought.
Regarding composite citations, 33 articles out 63 used them. The other authors felt that the basic numbering scheme is sufficient (as I have always done).
January 19, 2016
It is nice to have more concrete numbers. Some thoughts:
33/63 = 52%
Over half of articles in JACS use this. That is common!
I suspect also that you would see a higher proportion of composite refs in full papers than in communications, since communications have a 4 page limit, which translates to authors restricting their citations.
If you inspected only full papers in JACS, or review journals such as Chem. Rev., I'll wager you'd find a yet higher ratio.
19/63 = 30%
A third of all articles. That is also common, then!
Obviously, individual authors' needs vary, but I would put forward the same argument as above: I believe it's more prevalent in full papers and reviews than in communications. And for the same reasons: in a full paper or review, it's more likely there will be more citations which have to be arranged and put into context.
JACS, btw, publishes more communications than full papers, and basically no reviews at all. So it's a journal in which composite refs and descriptions are, in my view, less likely. Also, fewer authors will have the privilege of publishing in JACS than in all the other journals listed above.
But even so, with the (statistically unfair) journal choice, the relative percentages come out at 50% and 30% - which proves my point. I think a reference manager should be able to handle something used 30-50% (or more!) of the time in a major and broad scientific discipline.
January 19, 2016
edited January 19, 2016
Now I disagree with your assessment that choosing a JACS issue is statistically unfair. Biased perhaps, as any sample will be, but not unfair. JACS papers, whether full papers or communications, are much more representative of the written output of a scientist (chemist or otherwise) than reviews. How many reviews does an average researcher write every year, compared to the number of research articles?
But that's just me arguing for the sake of it :-) It doesn't cancel the fact that composite references, and to a somewhat lesser extent, descriptions in the bibliography, are not negligible occurrences in the literature of a significant science field. Therefore, supporting these practices would be a useful improvement to Zotero and the time spent figuring out the effective rules behind these practices will not be wasted. Hopefully the current discussion will be a beginning.
January 20, 2016
Thanks. The exact percentages don't matter much, but it good for us to have an idea of what are common and what are rare requirements.
Also, it would be very helpful if someone could compile a spreadsheet for journals that use composite references (e.g. via a public Google Docs spreadsheet). Ideally it would list, per journal: the journal title, the URL to the Instruction to Authors (where the composite citation format is described), and an URL to a publicly available (e.g. open access) formatted article from that journal that demonstrates the citation style. E.g. for Angewandte Chemie:
Angewandte Chemie International Edition
I'm a bit busy nowadays, and it would save me quite a bit of time if someone else could compile this.
January 22, 2016
edited January 22, 2016
Just an update: I only had time to check the ACS Style Guide
(for the non-chemists: in this book, the American Chemical Society gives extensive advice on good writing practices, preparation of figures, and so on). Chapter 14 deals with references, and I couldn't find a clear explanation or example of composite references. The closest thing I've seen is advice on grouping references by the same authors, mostly for print-only publications (thus essentially irrelevant for modern chemistry). Actually, the more simple numbered style is apparently encouraged at p.290:
"With numerical reference citations, start with 1 and number consecutively throughout the paper, including references in text and those in tables, figures, and other nontext components. If a reference is repeated, do not give it a new number; use the original reference number.
When citing more than one reference at one place by number in one of the numerical systems, list the numbers in ascending order and separate them by commas (without spaces as superscripts, with spaces on line), or if they are part of a consecutive series, use an en dash to indicate a range of three or more.
in the literature2,5,8 were reported3–5,10
in the literature (2, 5, 8) were reported (3–5, 10)"
I'll try to get some info from journal guidelines as suggested by Rintze above in the comings days.
December 26, 2018
I have been looking for an EndNote replacement. Zotero is an obvious candidate. However, I am also an organic chemist and using composite references is important to me (and my research group: 2 PhD students, 2 postdocs and a Masters student).
I read this thread with my group. We think this:
1. Chemists (and biochemists) are a large community. The reason they don't use Zotero (I know of no organic chemists who do; they all use Endnote), is because of the composite references thing.
2. The utility of composite references is reflected by the fact that EndNote have supported them for years. See here for the menu where they can be enabled:
3. The "rules" for composite references are simple: Basically, in any situation where you would have contiguous references cited, they are all cited under ONE number, and the papers appear in the bibliography under that one number, but under 1. (a) paper 1, (b) paper 2... That's about it.
4. The convention for this way of citing is not formulated officially in the the ACS style guide or the instructions of any specific journal, so far as we are aware. However, we can't think of a single chemistry journal that doesn't use this convention. It is that widespread.
We think it is unfortunate that aborel above seemed to spend so much time arguing from what he/she does personally in manuscripts. It seems the effort he/she expended was primarily on trying to persuade the Zotero community that composite references are not so necessary. But they absolutely are for very many people, for which reason they use EndNote.
The chemistry department I work in has approx 25 academic PIs (professors, lecturers, etc) and ALL of them use the composite reference convention in their manuscripts - I asked! I have international collaborators with whom I have authored both original papers (communications and full papers) and review articles. Composite references are always used.
Please, Zotero: we are not coders but we feel left out here. EndNote is hugely expensive and very buggy but we are left with no choice because of the composite references thing.
Please implement composite references.
December 27, 2018
There really isn’t an objection to adding them, but there hasn’t been a new version of CSL since this discussion occurred.
December 27, 2018
To add to what bwiernik says, here's the status of composite references:
1) Everyone working on citation styles understands they're essential for researchers working in chemistry and would like to support them.
2) The (time) resources for pushing forward citation-style related development are currently fairly limited, making progress slow
3) Composite references are fundamentally conceptually different from any other referencing systems used by any other discipline (no one else has a single bibliography entry with multiple items and your description under 3 oversimplifies things), making this a fairly involved change. I'm afraid it's not going to happen very soon.