BibLateX - basic customization

Question

Let's consider the MWE below

• I need the citations to truncate the authors' list to two followed by "et al", however, this setting doesn't work [based on Bernard's answer].

• Moreover, I would like the citation to be automatically encapsulated by square brackets.

• Finally, is there a quick fix to change the ampersand "&" with "and" phrase within the references?

• ADDED: (for style=ext-authoryear) how can I abbreviate first and second names of the authors with the initials? Solution: (giveninits=true in biblatex options).

Thank you in advance.

\documentclass{article}
\usepackage[citestyle=authoryear,style=apa,maxcitenames=2,mincitenames=2]{biblatex}

\begin{filecontents}{\jobname.bib}
@Article{Nachbagauer2015,
author="Karin Nachbagauer and Stefan Oberpeilsteiner and Karim Sherif and Wolfgang Steiner",
title="The Use of the Adjoint Method for Solving Typical Optimization Problems in Multibody Dynamics",
journal="Journal of Computational and Nonlinear Dynamics",
year="2015",
volume="10",
number="6",
doi="10.1115/1.4028417",
url="https://doi.org/10.1115/1.4028417"
}

    @Article{Dopico2014,
author="Daniel Dopico and Yitao Zhu and Adrian Sandu and Corina Sandu",
title="Direct and Adjoint Sensitivity Analysis of Ordinary Differential Equation Multibody Formulations",
journal="Journal of Computational and Nonlinear Dynamics",
year="2014",
volume="10",
number="1",
doi="10.1115/1.4026492",
url="https://doi.org/10.1115/1.4026492"
}
\end{filecontents}
\addbibresource{\jobname.bib}

\begin{document}
    Hallo world \\
    \cite{Nachbagauer2015}\\
    \cite{Dopico2014}
    \printbibliography
\end{document}

Answer 1

In general I recommend not to use biblatex-apa if you want a bibliography or citation style different from APA style. biblatex-apa was specifically written to comply to APA style in all its glory and with all its gory details. It can be extremely complicated to get biblatex-apa to change its behaviour even if "it should be easy".

(min|max)citenames

citestyle=authoryear,style=apa is equivalent to style=apa. biblatex-apa, in particular its citation style, does not obey (max|min)citenames as explained in APA style in biblatex with three authors and elsewhere because the APA requires special behaviour when truncating authors. With

style=apa,citestyle=authoryear

(which is equivalent to bibstyle=apa,citestyle=authoryear) the citation style is authoryear and (min|max)citenames is honoured.

square brackets for citations

That is very easy with styles of my biblatex-ext bundle. Simply use

citestyle=ext-authoryear

instead of citestyle=authoryear and issue

\DeclareOuterCiteDelims{parencite}{\bibopenbracket}{\bibclosebracket}

then set autocite=inline and use \autocite as your go-to citation command.

Replace "&" with "and"

This suggests that you actually don't want (bib)style=apa at all. Maybe style=authoryear or style=ext-authoryear already gives you what you want. If you insist on apa you need

\DeclareDelimFormat[bib,biblist]{finalnamedelim}{%
  \ifthenelse{\value{listcount}>\maxprtauth}
    {}
    {\ifthenelse{\value{liststop}>2}
       {\finalandcomma\addspace\bibstring{and}\space}
       {\addspace\bibstring{and}\space}}}

\DeclareDelimFormat[bib,biblist]{finalnamedelim:apa:family-given}{%
  \ifthenelse{\value{listcount}>\maxprtauth}
    {}
    {\finalandcomma\addspace\bibstring{and}\space}}

In total with apa bibliography style

\documentclass{article}
\usepackage[style=apa,citestyle=ext-authoryear,maxcitenames=2,mincitenames=2,autocite=inline]{biblatex}

\DeclareOuterCiteDelims{parencite}{\bibopenbracket}{\bibclosebracket}

\DeclareDelimFormat[bib,biblist]{finalnamedelim}{%
  \ifthenelse{\value{listcount}>\maxprtauth}
    {}
    {\ifthenelse{\value{liststop}>2}
       {\finalandcomma\addspace\bibstring{and}\space}
       {\addspace\bibstring{and}\space}}}

\DeclareDelimFormat[bib,biblist]{finalnamedelim:apa:family-given}{%
  \ifthenelse{\value{listcount}>\maxprtauth}
    {}
    {\finalandcomma\addspace\bibstring{and}\space}}

\begin{filecontents}{\jobname.bib}
@article{Nachbagauer2015,
  author  = {Karin Nachbagauer and Stefan Oberpeilsteiner and Karim Sherif and Wolfgang Steiner},
  title   = {The Use of the Adjoint Method for Solving Typical Optimization Problems in Multibody Dynamics},
  journal = {Journal of Computational and Nonlinear Dynamics},
  year    = {2015},
  volume  = {10},
  number  = {6},
  doi     = {10.1115/1.4028417},
}

@article{Dopico2014,
  author  = {Daniel Dopico and Yitao Zhu and Adrian Sandu and Corina Sandu},
  title   = {Direct and Adjoint Sensitivity Analysis of Ordinary Differential Equation Multibody Formulations},
  journal = {Journal of Computational and Nonlinear Dynamics},
  year    = {2014},
  volume  = {10},
  number  = {1},
  doi     = {10.1115/1.4026492},
}
\end{filecontents}
\addbibresource{\jobname.bib}

\begin{document}
  Lorem ipsum

  \autocite{Nachbagauer2015}

  \autocite{Dopico2014}

  \printbibliography
\end{document}

or with ext-authoryear bibliography style

\documentclass{article}
\usepackage[style=ext-authoryear,
  maxbibnames=999, maxcitenames=2, mincitenames=2,
  giveninits=true, uniquename=init,
  articlein=false, innamebeforetitle=true,
  autocite=inline]{biblatex}

\DeclareOuterCiteDelims{parencite}{\bibopenbracket}{\bibclosebracket}

\DeclareNameAlias{sortname}{family-given}

\addbibresource{biblatex-examples.bib}

\begin{document}
  Lorem ipsum

  \autocite{sigfridsson}

  \autocite{aksin}

  \autocite{companion}

  \printbibliography
\end{document}