Avoiding Citation Ambiguity When Using ‘Et Al.’ In Biblatex

Defining the Core Issue

When using the "et al." abbreviation in citations with BibLaTeX, ambiguity can arise if multiple works by the same first author are cited within the paper. Since "et al." omits the additional authors' names, readers cannot discern which specific work is being referenced if details are not provided to differentiate between similarly authored sources.

For example, if both Smith et al. 2019 and Smith et al. 2020 were cited within the text, a citation reading (Smith et al., 2021) would be unclear as to which source by Smith and others is being referred to. This prevents readers from efficiently evaluating and locating the appropriate work in the reference list.

Setting Up BibLaTeX for Disambiguation

Fortunately, BibLaTeX contains functionality to avoid citation ambiguity when using "et al." The "uniquename" option, enabled either globally or on a per-entry basis, automatically appends disambiguation information to the year in citations so that references to multiple works by the same first author are distinct.

For instance, with two sources by "Smith et al." the references would display as (Smith et al., 2019a) and (Smith et al., 2019b) in text for disfluent differentiation. This formatting happens automatically when "uniquename=true" is set in the BibLaTeX options or on specific BibTeX entries.

Demonstration of BibTeX Entry Examples

To demonstrate, if the following two BibTeX entries existed in the references file:

  author  = {Smith, John and Liu, Jane and Ahmed, Bob}, 
  title   = {Investigating Effects of Temperature},
  year    = {2019},
  journal = {Journal of Research},

  author  = {Smith, John and Ruiz, Carlos and Zhou, Alice}, 
  title   = {Examining Effects of Humidity},
  year    = {2020},
  journal = {Journal of Research},  

And "uniquename=true" was enabled, citations would automatically appear as (Smith et al., 2019a) for the first entry and (Smith et al., 2019b) for the second. This prevents ambiguity through the appended disambiguation letter a/b/c etc. based on the number of works by "Smith et al." in the reference list.

Formatting Cites for Unambiguous Identification

While the "uniquename" functionality covers many use cases, authors can also manually format citations to clearly identify sources without relying on automatic disambiguation.

Using Keywords like “prefix” and “suffix”

BibLaTeX offers prefix and suffix keywords to insert custom information before or after the year in a citation command. These can identify key details to differentiate sources by the same lead author.

For example, a citation could be formatted as:

\cite[prefix=Investigating, suffix=-Temperature]{smith2019}

Which would display as (Smith et al. [Investigating, 2019-Temperature]) to mark that specific work by "Smith et al., 2019."

Adding Identifying Information within the \cite Command

Relatedly, specific details can be inserted directly within the \cite command to unambiguously identify the work being referenced. Information like collaborators' names, source titles, or other metadata can clarify citations.

For example:

\cite[Smith, Jane Liu, and Bob Ahmed-2019]{smith2019}

Would output the citation as (Smith, Jane Liu, and Bob Ahmed-2019) unmistakably identifying the work and authors cited.

Code Examples of Properly Formatted Citations

To demonstrate applications, citations referring to the two previously defined BibTeX entries could be formatted as:

Investigating temperature effects \cite[prefix=Investigating, suffix=-Temperature]{smith2019}. Other factors were later considered like humidity \cite[Smith, Carlos Ruiz and Alice Zhou-2020]{smith2020}.

Outputting the disambiguated citations:

Investigating temperature effects (Smith et al. [Investigating, 2019-Temperature]). Other factors were later considered like humidity (Smith, Carlos Ruiz and Alice Zhou-2020).

With unique identifying information manually inserted, readers can properly discern which source is being referred to in each case.

Verifying Disambiguation through the Reference List

Following use of disambiguation techniques in text citations, the reference list at the end of a work should clearly confirm which source each citation points towards. This acts as the final step in avoiding ambiguity surrounding citations.

Examples Showing Clear Work Identification

Based on the previous BibTeX entries and citation examples, the final reference list would display as:


Smith, John, Jane Liu, and Bob Ahmed. 2019. "Investigating Effects of 
  Temperature." Journal of Research. 

Smith, John, Carlos Ruiz, and Alice Zhou. 2020. "Examining Effects of  
  Humidity." Journal of Research.

With full author and title details presented, readers can definitively match citations in text to the appropriate work. The first reference correlates to (Smith et al. [Investigating, 2019-Temperature]) in text, and the second to (Smith, Carlos Ruiz and Alice Zhou-2020).

The disambiguation tactics carry through to the final references, avoiding any remaining uncertainty over which source a citation refers to.


The use of "et al." allows condensing citation information through omitting additional author names. However, ambiguity arises when multiple works by the same lead author are cited. Enabling BibLaTeX's automatic "uniquename" disambiguation functionality prevents most issues by uniquely identifying sources in text citations.

In other cases, authors can manually insert identifying details like collaborator names or source titles using modifiers like "prefix" and "suffix" on \cite commands. Following disambiguation in text, the final reference list clearly attributes citations to the appropriate work.

With proper setup, BibLaTeX can avoid citation ambiguity when condensing references. Implementing the outlined techniques makes accurate identification of sources possible even when using "et al." for concise citations. Authors have full control over disambiguation to optimize clarity for readers.

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