Biblatex-apa error message when compiling

Question

I'm trying to write a document with APA 6th edition referencing. I'm using Texmaker 5.0.2 and Windows 10 to do so. I have been told that the biblatex-apa package is the best option for APA 6th edition referencing within LaTeX. However, when I attempt to do so I get the error:

using the MWE:

\documentclass[11pt, twoside]{article}

%document foramtting
\usepackage[margin = 2.5cm]{geometry}

%Referencing package
\usepackage[
    backend = biber,
    style = apa,
    natbib = true
    ]{biblatex}
\addbibresource{citations.bib}

\begin{document}

This is a test for biblatex-apa. \citep{IForImagNumb,BriefHistOfeigamma,HistOfMaths}

\printbibliography

\end{document}

and the bib file

@book{HistOfMaths,
    author = {Boyer, Carl B. and Merzbch, Uta C.},
    year = {1991},
    title = {A history of mathematics},
    edition = {2nd},
    city = {New York},
    publisher = {Wiley}
}

@online{DrawGraph,
    author = {Kummer, J.},
    title = {Draw Function Graph},
    url = {https://rechneronline.de/function-graphs/},
    lastchecked = {2018-01-05}
}

@misc{PaintThreeD,
    author = {Microsoft,},
    title = {Paint 3d (Version 5.1806.20057.0) [Computer software]},
    year = {2017},
    address = {Redmond, Washington},
    publisher = {Author},
    url = {https://www.microsoft.com/en-us/p/paint-3d/9nblggh5fv99}
}

@book{Elements,
    author = {Euclid,},
    translator = {Heath, T. L.},
    editor = {Densmore, D.},
    originalyear = {2002},
    year = {2017},
    title = {Euclid's Elements},
    address = {Santa Fe, New Mexico},
    publisher = {Green Lion Press}
}

@book{Cantor,
    author = {Cantor, Georg},
    translator = {Jourdain, Philip E. B.},
    originalyear = {1915},
    year = {2009},
    title = {Contributions to the Founding of the Theory of Transfinite Numbers},
    address = {London},
    publisher = {BiblioLife}
}

@article{BriefHistOfeigamma,
    author = {Debnath, Lokenath},
    year = {2015},
    title = {A brief history of the most remarkable numbers e, i, and $\gamma$ in mathematical sciences with applications},
    journaltitle = {Journal of Mathematical Education in Science and Technology},
    volume = {46},
    issue = {6},
    pages = {853-878},
    doi = {10.1080/0020739X.2015.1015266}
}

@article{IForImagNumb,
    author = {Curcio, Liliana},
    year = {2017},
    title = {I for Imaginary Numbers},
    journaltitle = {Lettera Mathematica},
    volume = {5},
    issue = {2},
    pages = {125-129},
    doi = {10.1007/s40329-017-0172-6}
}

@article{PhysNatureOfImagNumb,
    author = {Antonov, Alexander Alexandrovich},
    year = {2016},
    title = {Physical Reality and Nature of Imaginary, Complex and Hypercomplex Numbers},
    journaltitle = {General Mathematics Notes},
    volume = {35},
    issue = {2},
    pages = {40-63},
    url = {http://www.geman.in/yahoo_site_admin/assets/docs/4_GMN-10932-V35N2.31895146.pdf}
}

@article{ImagXtrmNumb,
    author = {Liu, Liping},
    year = {2013},
    title = {Imaginary numbers for combining linear equation models via Dempster's rule},
    journaltitle = {International Journal of Approximate Reasoning},
    volume = {55},
    issue = {1},
    pages = {294-310},
    doi = {10.1016/j.ijar.2013.09.004}
}

Line 19 in the error message is inbetween \printbibliography and \end{document}. I've tried deleting the whitespace, but Texmaker returns an error for line 19 (the \end{document} line).

Regards,

A LaTeX novice

Answer 1

biblatex-apa changes the case of @article titles from Title Case to sentence case. The case changing macro is a bit fragile and so some content like maths and other special macros need to be escaped in curly brackets.

title = {A brief history of the most remarkable numbers e, i, and {$\gamma$} in mathematical sciences with applications},

The MWE

\documentclass[11pt, twoside]{article}

\usepackage[
    backend = biber,
    style = apa,
    ]{biblatex}

%\usepackage{filecontents}
\begin{filecontents}{\jobname.bib}
@article{BriefHistOfeigamma,
    author = {Debnath, Lokenath},
    year = {2015},
    title = {A brief history of the most remarkable numbers e, i, and {$\gamma$} in mathematical sciences with applications},
    journaltitle = {Journal of Mathematical Education in Science and Technology},
    volume = {46},
    issue = {6},
    pages = {853-878},
    doi = {10.1080/0020739X.2015.1015266}
}
\end{filecontents}
\addbibresource{\jobname.bib}

\begin{document}
\nocite{BriefHistOfeigamma}
\printbibliography
\end{document}

throws no error and gives the output

You may want to double check if it should be

title = {A brief history of the most remarkable numbers {$e$}, {$i$}, and {$\gamma$} in mathematical sciences with applications},

with e and i in math mode as well.