А? Знак показывает вместо ссылок в шаблоне jss пакета riciespackage

Question

У меня проблемы с добавлением ссылок в шаблон jss. Я использовал шаблон elsevier без проблем. Я также попытался изменить @reference на \cite{ссылки} или \citep{ссылки}, но a? Знак появляется там, где должны быть ссылки. Я чувствую, что неправильно указываю на файл.bib. Есть идеи, что я делаю не так?

В качестве примера у меня есть следующий код из статьи, которую я пытаюсь написать с цитатой в последнем слове последнего абзаца:

---
author:
  - name: Derek Corcoran
    affiliation: University of Missouri
    address: >
    First line
    Second line
email: [e-mail]
url: http://rstudio.com

formatted: "Selecting priority areas from diversity and individual species abundance \\pkg{DiversityOccupancy}"
short:     "\\pkg{DiversityOccupancy}: Selecting Priority Areas"
abstract: >
Lately occupancy modeling has been vastly used as a tool for ecological research and management planing. However mostly it is used by interpreting single species models. We present the \pkg{DiversityOccupancy} in the \proglang{R} environment. The objective of this package is to simultaneously model factors associated with occupancy and abundance of individual species using a detection history file, and to use predicted abundances to calculate species diversity for each sampling site. The package then models factor(s) associated with among-site species diversity, which can then be combined with spatial data to identify areas that contain both high abundance of species of conservation concern and high species diversity.
keywords:
# at least one keyword must be supplied
formatted: [ "\\pkg{DiversityOccupancy}", Occupancy Modeling, "\\proglang{R}"]
plain:     [keywords, not capitalized, Occupancy modeling]
preamble: >
\usepackage{amsmath}
output:
  rticles::jss_article:
    citation_package: natbib
bibliography: Derek.bib
---




# Introduction

In the last decade, Occupancy modeling has been used more and more as a 
method to account for how species respond to environmental or anthropogenic 
factors. It has also been shown to be useful as a species distribution 
modeling tool when species have imperfect detection 
\cite{mackenzie_estimating_2002}. 

В моем файле.bib форматируется бумага так:

@article{mackenzie_estimating_2002,
    title = {Estimating site occupancy rates when detection probabilities are less than one},
    volume = {83},
    url = {http://www.esajournals.org/doi/abs/10.1890/0012-9658(2002)083%5B2248:ESORWD%5D2.0.CO%3B2},
    number = {8},
    urldate = {2016-01-13},
    journal = {Ecology},
    author = {MacKenzie, Darryl I. and Nichols, James D. and Lachman, Gideon B. and Droege, Sam and Andrew Royle, J. and Langtimm, Catherine A.},
    year = {2002},
    pages = {2248--2255},
    file = {[PDF] de uvm.edu:/home/derek/.zotero/zotero/b7w3ygs6.default/zotero/storage/HSJAQTQG/MacKenzie et al. - 2002 - Estimating site occupancy rates when detection pro.pdf:application/pdf;Snapshot:/home/derek/.zotero/zotero/b7w3ygs6.default/zotero/storage/G45M4BNP/abstract.html:text/html}
}