Let's take this reference in `References.bib`
````
@article{Cronbach_1951,
	doi = {10.1007/bf02310555},
	year = 1951,
	month = {sep},
	publisher = {Springer Science and Business Media {LLC}},
	vol = {16},
	number = {3},
	pages = {297--334},
	author = {Lee J. Cronbach},
	title = {Coefficient alpha and the internal structure of tests},
	journal = {Psychometrika}
}
```` 

If we do with no reference
````markdown
---
title: "Untitled"
format: typst
bibliography: References.bib
bibliographystyle: "chicago-author-date"
keep-typ: true
---

Hello
````

There will be at the bottom of the file 

````
#set bibliography(style: "chicago-author-date")

#bibliography("References.bib")
````

It will cause typst to create a Bibliography section anyway. 


When a citation is added, it seems Pandoc will add some bibliography content

````markdown
---
title: "Untitled"
format: typst
bibliography: References.bib
bibliographystyle: "chicago-author-date"
---

Hello [@Cronbach_1951]

````

````
#label("refs")
#label("ref-Cronbach_1951")
Cronbach, Lee J. 1951. “Coefficient Alpha and the Internal Structure of Tests.” #emph[Psychometrika], no. 3 (September): 297–334. #link("https://doi.org/10.1007/bf02310555").

#set bibliography(style: "chicago-author-date")


#bibliography("References.bib")
````

It seems from https://github.com/jgm/pandoc/issues/8763#issuecomment-1500387547 that it requires some tweak when citation processing is done by Pandoc. (which happens when citeproc is used)

Adding `citeproc: false` to YAML header
````markdown 
---
title: "Untitled"
format: typst
bibliography: References.bib
bibliographystyle: "chicago-author-date"
citeproc: false
---

Hello [@Cronbach_1951]
````

Will correctly output only the native typst citation processing. 


So it seems : 

* We should default to ``citeproc: false` with typst 
* Or we need to pass `typst-citations` as a format 

_Originally posted by @cderv in https://github.com/quarto-dev/quarto-cli/discussions/5502#discussioncomment-5915093_
cderv
2023-05-16T10:53:46Z
cderv
bug typst
v1.4
closed
References are inserted twice with default typst format 
https://github.com/quarto-dev/quarto-cli/issues/5560