Citation not working

Question

In my .bib file I have two entries as follows:

@book{si20,
    title = {Introduction to Econometrics with R},
    author = {Schmelzer, Martin Arnold, Alexander Gerber, and Martin, Christoph Hanck},
    url = {https://www.econometrics-with-r.org/},
    urldate = {2020-10-02},
    year = {2020}
}
@Article{pcalg,
    title = {Causal Inference Using Graphical Models with the {R}
      Package {pcalg}},
    author = {Markus Kalisch and Martin M"achler and Diego Colombo and
      Marloes H. Maathuis and Peter B"uhlmann},
    journal = {Journal of Statistical Software},
    year = {2012},
    volume = {47},
    number = {11},
    pages = {1--26},
    url = {https://www.jstatsoft.org/article/view/v047i11},
  }

My document looks like this:

\documentclass{article}
\usepackage[utf8]{inputenc}
\title{Test citations}
\author{Jaime Sevilla}
\date{November 2020}
\usepackage[
backend=biber, natbib,
style=numeric
]{biblatex}
\addbibresource{name.bib}
\begin{document}
\maketitle
\section{Introduction}
\cite{si20}
\cite{pcalg}
\printbibliography
\end{document}

At first sight I would think that both bib entries are correctly formatted. But only the second one works!

What is going on? How do I fix the first bib entry?

Answer 1

It looks like the author field in the si20 entry is missing some "and"s to separate the authors. The correct formatting for si20 should look something like this:

@book{si20,
    title = {Introduction to Econometrics with R},
    author = {Hanck, Christoph and Arnold, Martin and Gerber, Alexander and Schmelzer, Martin},
    url = {https://www.econometrics-with-r.org/},
    urldate = {2020-10-02},
    year = {2020}
}