Numeric .csl styles causing misalignment of pdf bibliography in RMarkdown

Question

My goal is to generate a numeric bibliography in pdf using Rmarkdown and a .csl. However, no matter which .csl file I use, the first word of the references are all slightly misaligned from each other. I suspect it has something to do with how latex justifies but I don't know it or pandoc well enough to figure it out or fix it. Ideally I'm looking for a way to fix it in Rmarkdown. As far as I can tell this doesn't happen with non-numeric styles.

MRE:

First get some numeric .csl files, as far as I can tell it happens with any of them. https://www.zotero.org/styles is a good source, good examples are Nature (nature.csl), Science (science.csl), or Biomed Central (biomed-central.csl).

Then run this to generate a sample bib:

knitr::write_bib(c("knitr", "stringr", "ggplot2"), "test.bib")

Then knit this Rmd file:

---
title: "test"
output: pdf_document
bibliography: test.bib
csl: biomed-central.csl # whatever numeric .csl
---

# Citations

@R-ggplot2 @R-knitr @R-stringr @ggplot22016 @knitr2015 @knitr2014 

# References

Results:

With biomed-central.csl:

With nature.csl (slight but still there):

With science.csl:

I have also tried different latex engines to no avail.

sessioninfo:

R version 3.6.2 (2019-12-12)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows 10 x64 (build 18362)

Matrix products: default

locale:
[1] LC_COLLATE=English_United States.1252  LC_CTYPE=English_United States.1252    LC_MONETARY=English_United States.1252 LC_NUMERIC=C                          
[5] LC_TIME=English_United States.1252    

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
 [1] forcats_0.4.0   stringr_1.4.0   dplyr_0.8.3     purrr_0.3.3     readr_1.3.1     tidyr_1.0.0     tibble_2.1.3    ggplot2_3.2.1   tidyverse_1.3.0 rmarkdown_2.1.1
[11] knitr_1.27      here_0.1       

loaded via a namespace (and not attached):
 [1] tinytex_0.19     tidyselect_0.2.5 xfun_0.12        haven_2.2.0      lattice_0.20-38  colorspace_1.4-1 generics_0.0.2   vctrs_0.2.1      htmltools_0.4.0  yaml_2.2.0      
[11] rlang_0.4.2      pillar_1.4.3     withr_2.1.2      glue_1.3.1       DBI_1.1.0        dbplyr_1.4.2     modelr_0.1.5     readxl_1.3.1     lifecycle_0.1.0  cellranger_1.1.0
[21] munsell_0.5.0    gtable_0.3.0     rvest_0.3.5      evaluate_0.14    labeling_0.3     fansi_0.4.1      highr_0.8        broom_0.5.3      Rcpp_1.0.3       scales_1.1.0    
[31] backports_1.1.5  jsonlite_1.6     farver_2.0.3     fs_1.3.1         hms_0.5.3        digest_0.6.23    stringi_1.4.4    grid_3.6.2       rprojroot_1.3-2  cli_2.0.1       
[41] tools_3.6.2      magrittr_1.5     lazyeval_0.2.2   crayon_1.3.4     pkgconfig_2.0.3  zeallot_0.1.0    ellipsis_0.3.0   xml2_1.2.2       reprex_0.3.0     lubridate_1.7.4 
[51] assertthat_0.2.1 httr_1.4.1       rstudioapi_0.10  R6_2.4.1         nlme_3.1-142     compiler_3.6.2  

Answer 1

\raggedright fixes the problem:

---
title: "test"
output: pdf_document
bibliography: test.bib
csl: biomed-central.csl # whatever numeric .csl
---

# Citations

@R-ggplot2 @R-knitr @R-stringr @ggplot22016 @knitr2015 @knitr2014 

\raggedright
# References