I have to write a report using APA style bibliography, using this minimal example:




    author = {Knuth, Donald E.},
    year = {1986},
    title = {The \TeX book},






Doesn't end processing, the bibliography is never printed, instead:

Package biblatex Info: No input encoding detected.
(biblatex)             Assuming 'ascii'.
Package biblatex Info: Automatic encoding selection.
(biblatex)             Assuming data encoding 'ascii'.
\openout3 = `test.bcf'.

Package biblatex Info: Trying to load bibliographic data...
Package biblatex Info: ... file 'test.bbl' found.
Package biblatex Info: Reference section=0 on input line 19.
Package biblatex Info: Reference segment=0 on input line 19.

LaTeX Warning: Citation '*' on page 1 undefined on input line 21.

! Undefined control sequence.
<argument> \mkbibdateapalongextra 
                                  {year}{month}{day}\iffieldundef {endyear}{...

is found in the log file. If I use citestyle, this error doesn't appear. style produces the same problem. This answer makes allusion that I need to define just one language in babel, but using language=american as recommended produce the same result.

  • See also problems using apa6e with biblatex-apa. Where in the answer did you find the allusion that one may only load one language? In the example it was important that one could not alias english to american-apa with \DeclareLanguageMapping{english}{american-apa}. I have now added a short paragraph about the general problem to the answer. But please let me know what I can do to avoid misunderstandings.
    – moewe
    Feb 29, 2016 at 6:19

1 Answer 1


After having re-read again the manual, I saw in the "Use" section:

Specify the style in the usual way when loading BibLATEX. If you are using babel:


I wasn't using the \DeclareLanguageMapping command that matched my babel preferences. Using



Fixed the issue. Must make sure that babel's and DeclareLanguageMapping languages matches, and that <texmf>/tex/latex/biblatex/lbx/<language>-apa.lbx has the language present.

  • More recent versions of biblatex-apa apply \DeclareLanguageMapping automatically for all languages. So now the only bottleneck is whether or not biblatex-apa has a <language>-apa.lbx for your document language <language>.
    – moewe
    Feb 20, 2019 at 8:45
  • @moewe that's super. Do you have in hand the specific commit/version for this change? I tried reading the RELEASE file, but I remember still needing it in late '17 on Debian testing, which shouldn't happen.
    – Braiam
    Feb 21, 2019 at 15:19
  • biblatex-apa v7.5 (2017-11-05) and biblatex 3.8 (2017-11-04).
    – moewe
    Feb 21, 2019 at 15:20

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