参考书目中的无关条目（biblatex）

Question

这是我的参考书目的图片。

如图所示，LaTeX 在我的参考书目中添加了一个额外条目。请注意，我的 中没有此参考文献references.bib，也没有任何标有1在文本本身中。

以下是我的序言，希望对您有帮助：

\documentclass[a4paper,12pt,twoside,openright,notitlepage]{report}

\usepackage[UKenglish]{babel}
\usepackage[style=numeric]{biblatex}
\usepackage[printonlyused]{acronym}
\usepackage{setspace}
\usepackage{fullpage}
\usepackage{float}
\usepackage{graphicx}
\usepackage{subfig}
\usepackage{array}
\usepackage{amssymb}
\usepackage{gensymb}
\usepackage{listings}
\usepackage{xspace}
\usepackage{datetime}
\usepackage{url}
\usepackage{color}
\settimeformat{hhmmsstime}
\doublespacing
\raggedbottom
\addbibresource{references.bib}
\makeatletter
\newcommand\ackname{Acknowledgements}
\if@titlepage
  \newenvironment{acknowledgements}{%
      \titlepage
      \null\vfil
      \@beginparpenalty\@lowpenalty
      \begin{center}%
        \bfseries \ackname
        \@endparpenalty\@M
      \end{center}}%
     {\par\vfil\null\endtitlepage}
\else
  \newenvironment{acknowledgements}{%
      \if@twocolumn
        \section*{\abstractname}%
      \else
        \small
        \begin{center}%
          {\bfseries \ackname\vspace{-.5em}\vspace{\z@}}%
        \end{center}%
        \quotation
      \fi}
      {\if@twocolumn\else\endquotation\fi}
\fi
\makeatother

\renewcommand{\thefootnote}{\alph{footnote}}

\newcolumntype{L}{>{\centering\arraybackslash}m{0.5\textwidth}}

\newcommand{\latex}{\LaTeX\xspace}
\newcommand{\tex}{\TeX\xspace}

\lstset{
numbers=left, 
numberstyle=\small, 
numbersep=8pt, 
frame = single, 
language=R, 
framexleftmargin=15pt}

以下是我的references.bib

@online{QuickR,
author = {Robert I. Kabacoff},
title = {About Quick-R},
year = {2012},
url = {http://www.statmethods.net/},
}


@online{StackOverflow,
author = {Stack Exchange Inc},
title = {Welcome to Stack Overflow},
year = {2014},
url = {http://stackoverflow.com/about},
}

编辑：文件可以在这里找到：https://www.sharelatex.com/project/52da502aa5d18bc436000021