Hello all, may I ask for help on the question that I have posted in tex.stackexchange.com/a/115825/23594

I am trying to have % and # in the url in the bibliography while using backref

@Ahmad you should build a minimal (not) working example; use package filecontents to include two entrys of your used bibfile. Then we can see what happend and try to help you. Now there is too less information ...

Sure. I am going to do it right now.

Here is the minimal code:

\documentclass[
                openright,
                titlepage, numbers=noenddot, headinclude,%1headlines,
                footinclude=true, cleardoublepage=empty,
                BCOR=30mm, paper=letter, fontsize=11pt, % Binding correction, paper type and font size
                ngerman, american, % Languages
                ]{scrreprt}


\PassOptionsToPackage{%
                    eulerchapternumbers,
                    listings,
                    pdfspacing,
                    subfig,

The bibliography file contains the following citation:

@misc{chdkiller,
  author = {},
  title = {{Centers for Disease Control and Prevention. Vital Statistics Public Use
  Data Files - 2008 Mortality Multiple Cause Files}},
  howpublished = "\url{cdc.gov/nchs/data_access/…}",
  year = {2012},
  note = "[Online; accessed March 7, 2012]"
}

If I remove # from the url in the bibliography file, it will work.

I am using the bibliography style file posted in tex.stackexchange.com/a/106169/23594

It seems backref package does not like % and # in the urls.

@Ahmad please add your MWE in your question ...

@Kurt: I am using MikTeX 2.9.

@Kurt: sure

@Kurt: I just added it.

@Ahmad were does style abbrvunsrtnatcomes from? Gaves me an error: unknown ...

Ah, now I saw your link ...

@Kurt: sure.

@DavidCarlisle ! LaTeX Error: File anything.sty' not found.`

I have updated my question in tex.stackexchange.com/a/115825/23594

@dıʞsdoʇ I was thinking more about the detexfaq site (that you host?). I had also seen that you had asked Joseph, Paulo and Marco(Martin?) to write up something there. So, I thought you'd be happy to see a contribution. :)

@DavidCarlisle Hello! How's the day today?

@kan Contributions are not only welcome, but very welcome.

@kan You can edit without logging in

@PauloCereda Having done lot's of coding in Lips I agree (car, cdr)

\def\@car#1#2\@nil{#1}
\def\@cdr#1#2\@nil{#2}

@DavidCarlisle Like winter here

@dıʞsdoʇ Which will take O(n) time each if I'm not mistaken...

@StephanLehmke they are part of the latex format:-) O(something) but with a small factor as the scan to discard the tail as #2 is proportional to the length of the data of the list (not the number of items) but is relatively quick compared to something that has lower order but requires more expansions.

@DavidCarlisle Still I think it's good to keep in mind that TeX is not turning to Lisp by defining \car and \cdr this way. With Lisp you're used to define a map by iterating car and cdr. With TeX it's better to code the list with a "helper macro" and implement the map by just executing the list.

@StephanLehmke Yes I think that's what Leslie discovered:-) The original comments in LaTeX 2.0x were in a lispish pseudo-code and \@car and \@cdr were defined in the very earliest versions of LaTeX but they are in fact only used a couple of times each, one of which is in the LaTeX2e macro:-) Almost all List processing in the format happens (even in latex2.09) by defining \@elt then executing \@elt a \@elt b ...

@DavidCarlisle Which is more-or-less how the non-expandable sequence mappings are set up in expl3 :-)

@JosephWright Well I wasn't assuming to tell you lot anything new ;-)

Still it's odd how popular comma-separated lists still are in TeX :-(

@StephanLehmke Useful for user input or saving easily to auxiliary files

@StephanLehmke The expl3 view is that they are 'handy' but limited

@StephanLehmke We've had a few different implementations before arriving at the current one :-)

@JosephWright I think this is superficial in the sense of self-fulfillingness.

@StephanLehmke At one point I suggested dropping comma-list support from expl3, but this did not fly, not least because if you want to allow the internal form to vary, the only way to add to a 'sequence' is one item at a time while a comma list always has the same form so can be set in 'one shot'

@JosephWright Uh wut

What do you mean by "allow the internal form to vary"?

@StephanLehmke If you want to define a list of items, with a comma list you know you can do \def\mylist{a,b,c,d,e}. On the other hand, if you have some arbitrary sequence form the only way to do it is \addtoseq\myseq{a}\addtoseq\myseq{b}\addtoseq\myseq{c}..., unless you are going to tie your use of the sequence to the way you've defined the internals (\@elt in LaTeX2e).

@StephanLehmke One of the ideas in expl3 is that the interfaces are defined but the implementation can be changed, provided we don't alter the expected behaviour.

@JosephWright Well it's the same as asking for the comma to vary, isn't it? Why is one form allowed to have a fixed syntax and the other not?

Thus only code inside l3seq should have to 'know' how sequences are implemented

You have a specific top-level abstraction layer and variation happens below that.

@StephanLehmke As I said, a comma list is relatively straightforward and is by definition delimited by commas, while some 'sequence data structure' is not

It's a compromise between 'purity' and realism

@JosephWright Which is a variation of specification and has nothing to do with implementation, which is inherently inferior for the comma-separated list.

@StephanLehmke But at the interface level (say in a document), using a comma list is a question of realism. Same applies to a keyval list: it is tied to the interface to some extent.

As a counterpart of "some sequence data structure", you need "some delimited data structure". Fixing the comma is unfair in comparison.

@JosephWright As I said, the comma list is straightforward by habit. There are other languages without comma lists.

@StephanLehmke I'm sure