diff --git a/bibliography.bib b/bibliography.bib
new file mode 100644
index 0000000000000000000000000000000000000000..c8df73f2f13578de9b71ab2cb1f73795377b6940
--- /dev/null
+++ b/bibliography.bib
@@ -0,0 +1,420 @@
+ ##############
+ # R packages
+
+ @Manual{baseR,
+ title = {R: A Language and Environment for Statistical Computing},
+ author = {{R Core Team}},
+ organization = {R Foundation for Statistical Computing},
+ address = {Vienna, Austria},
+ year = {2016},
+ url = {https://www.R-project.org/},
+ }
+ @Manual{bookdown,
+ title = {bookdown: Authoring Books and Technical Documents with R Markdown},
+ author = {Yihui Xie},
+ year = {2018},
+ note = {R package version 0.9},
+ url = {https://github.com/rstudio/bookdown},
+ }
+
+ @Manual{broom,
+ title = {broom: Convert Statistical Analysis Objects into Tidy Data Frames},
+ author = {David Robinson},
+ year = {2016},
+ note = {R package version 0.4.1},
+ url = {https://CRAN.R-project.org/package=broom},
+ }
+ @Book{car,
+ title = {An {R} Companion to Applied Regression},
+ edition = {Second},
+ author = {John Fox and Sanford Weisberg},
+ year = {2011},
+ publisher = {Sage},
+ address = {Thousand Oaks {CA}},
+ url = {http://socserv.socsci.mcmaster.ca/jfox/Books/Companion},
+ }
+
+ @Manual{data.table,
+ title = {data.table: Extension of Data.frame},
+ author = {M Dowle and A Srinivasan and T Short and S Lianoglou with contributions from R Saporta and E Antonyan},
+ year = {2015},
+ note = {R package version 1.9.6},
+ url = {https://CRAN.R-project.org/package=data.table},
+ }
+
+ @Manual{doBy,
+ title = {doBy: Groupwise Statistics, LSmeans, Linear Contrasts, Utilities},
+ author = {Søren Højsgaard and Ulrich Halekoh},
+ year = {2016},
+ note = {R package version 4.5-15},
+ url = {https://CRAN.R-project.org/package=doBy},
+ }
+
+ @Manual{dplyr,
+ title = {dplyr: A Grammar of Data Manipulation},
+ author = {Hadley Wickham and Romain Francois},
+ year = {2016},
+ note = {R package version 0.5.0},
+ url = {https://CRAN.R-project.org/package=dplyr},
+ }
+ @Article{drake,
+ title = {The drake R package: a pipeline toolkit for reproducibility and high-performance computing},
+ author = {William Michael Landau},
+ journal = {Journal of Open Source Software},
+ year = {2018},
+ volume = {3},
+ number = {21},
+ url = {https://doi.org/10.21105/joss.00550},
+ }
+ @Manual{dtplyr,
+ title = {dtplyr: Data Table Back-End for 'dplyr'},
+ author = {Hadley Wickham},
+ year = {2016},
+ note = {R package version 0.0.1},
+ url = {https://CRAN.R-project.org/package=dtplyr},
+ }
+
+ @Manual{fgarch,
+ title = {fGarch: Rmetrics - Autoregressive Conditional Heteroskedastic Modelling},
+ author = {Diethelm Wuertz and Yohan Chalabi with contribution from Michal Miklovic and Chris Boudt and Pierre Chausse and {others}},
+ year = {2016},
+ note = {R package version 3010.82.1},
+ url = {https://CRAN.R-project.org/package=fGarch},
+ }
+
+ @Manual{foreign,
+ title = {foreign: Read Data Stored by Minitab, S, SAS, SPSS, Stata, Systat, Weka, dBase, ...},
+ author = {{R Core Team}},
+ year = {2015},
+ note = {R package version 0.8-66},
+ url = {https://CRAN.R-project.org/package=foreign},
+ }
+
+ @Book{fox_car,
+ title = {An {R} Companion to Applied Regression},
+ edition = {Second},
+ author = {John Fox and Sanford Weisberg},
+ year = {2011},
+ publisher = {Sage},
+ address = {Thousand Oaks {CA}},
+ url = {http://socserv.socsci.mcmaster.ca/jfox/Books/Companion},
+ }
+
+ @Manual{gdata,
+ title = {gdata: Various R Programming Tools for Data Manipulation},
+ author = {Gregory R. Warnes and Ben Bolker and Gregor Gorjanc and Gabor Grothendieck and Ales Korosec and Thomas Lumley and Don MacQueen and Arni Magnusson and Jim Rogers and {others}},
+ year = {2015},
+ note = {R package version 2.17.0},
+ url = {https://CRAN.R-project.org/package=gdata},
+ }
+ @Manual{ggjoy,
+ title = {ggjoy: Joyplots in ggplot2},
+ author = {Claus O. Wilke},
+ year = {2017},
+ note = {R package version 0.1},
+ url = {https://github.com/clauswilke/ggjoy},
+ }
+ @Book{ggplot2,
+ author = {Hadley Wickham},
+ title = {ggplot2: Elegant Graphics for Data Analysis},
+ publisher = {Springer-Verlag New York},
+ year = {2009},
+ isbn = {978-0-387-98140-6},
+ url = {http://ggplot2.org},
+ }
+ @Article{ggmap,
+ author = {David Kahle and Hadley Wickham},
+ title = {ggmap: Spatial Visualization with ggplot2},
+ journal = {The R Journal},
+ year = {2013},
+ volume = {5},
+ number = {1},
+ pages = {144--161},
+ url = {http://journal.r-project.org/archive/2013-1/kahle-wickham.pdf},
+ }
+ @Manual{gridExtra,
+ title = {gridExtra: Miscellaneous Functions for "Grid" Graphics},
+ author = {Baptiste Auguie},
+ year = {2016},
+ note = {R package version 2.2.1},
+ url = {https://CRAN.R-project.org/package=gridExtra},
+ }
+ @Manual{here,
+ title = {here: A Simpler Way to Find Your Files},
+ author = {Kirill Müller},
+ year = {2017},
+ note = {R package version 0.1},
+ url = {https://CRAN.R-project.org/package=here},
+ }
+ @Manual{Hmisc,
+ title = {Hmisc: Harrell Miscellaneous},
+ author = {Frank E {Harrell Jr} and with contributions from Charles Dupont and many others.},
+ year = {2016},
+ note = {R package version 3.17-4},
+ url = {https://CRAN.R-project.org/package=Hmisc},
+ }
+@Manual{kableExtra,
+ title = {kableExtra: Construct Complex Table with 'kable' and Pipe Syntax},
+ author = {Hao Zhu},
+ year = {2019},
+ note = {R package version 1.0.1},
+ url = {https://CRAN.R-project.org/package=kableExtra},
+ }
+ @Manual{knitr,
+ title = {knitr: A General-Purpose Package for Dynamic Report Generation in R},
+ author = {Yihui Xie},
+ year = {2016},
+ url = {https://CRAN.R-project.org/package=knitr},
+ }
+ @Article{lmtest,
+ title = {Diagnostic Checking in Regression Relationships},
+ author = {Achim Zeileis and Torsten Hothorn},
+ journal = {R News},
+ year = {2002},
+ volume = {2},
+ number = {3},
+ pages = {7--10},
+ url = {https://CRAN.R-project.org/doc/Rnews/},
+ }
+ @Article{lubridate,
+ title = {Dates and Times Made Easy with {lubridate}},
+ author = {Garrett Grolemund and Hadley Wickham},
+ journal = {Journal of Statistical Software},
+ year = {2011},
+ volume = {40},
+ number = {3},
+ pages = {1--25},
+ url = {http://www.jstatsoft.org/v40/i03/},
+ }
+ @Manual{mapproj,
+ title = {mapproj: Map Projections},
+ author = {Doug McIlroy. Packaged for R by Ray Brownrigg and Thomas P Minka and transition to Plan 9 codebase by Roger Bivand.},
+ year = {2015},
+ note = {R package version 1.2-4},
+ url = {https://CRAN.R-project.org/package=mapproj},
+ }
+
+ @Manual{maptools,
+ title = {maptools: Tools for Reading and Handling Spatial Objects},
+ author = {Roger Bivand and Nicholas Lewin-Koh},
+ year = {2016},
+ note = {R package version 0.8-39},
+ url = {https://CRAN.R-project.org/package=maptools},
+ }
+
+ @Article{mefa,
+ title = {Processing Ecological Data in {R} with the {mefa} Package},
+ author = {P\'eter S\'olymos},
+ journal = {Journal of Statistical Software},
+ year = {2009},
+ volume = {29},
+ number = {8},
+ pages = {1--28},
+ url = {http://www.jstatsoft.org/v29/i08/},
+ }
+ @Article{openair,
+ title = {openair --- An R package for air quality data analysis},
+ author = {David C. Carslaw and Karl Ropkins},
+ journal = {Environmental Modelling & Software},
+ volume = {27--28},
+ number = {0},
+ pages = {52--61},
+ year = {2012},
+ issn = {1364-8152},
+ doi = {10.1016/j.envsoft.2011.09.008},
+ }
+ @Article{plm,
+ title = {Panel Data Econometrics in {R}: The {plm} Package},
+ author = {Yves Croissant and Giovanni Millo},
+ journal = {Journal of Statistical Software},
+ year = {2008},
+ volume = {27},
+ number = {2},
+ url = {http://www.jstatsoft.org/v27/i02/},
+ }
+ @Manual{plotly,
+ title = {plotly: Create Interactive Web Graphics via 'plotly.js'},
+ author = {Carson Sievert and Chris Parmer and Toby Hocking and Scott Chamberlain and Karthik Ram and Marianne Corvellec and Pedro Despouy},
+ year = {2016},
+ note = {R package version 4.5.6},
+ url = {https://CRAN.R-project.org/package=plotly},
+ }
+ @Article{plyr,
+ title = {The Split-Apply-Combine Strategy for Data Analysis},
+ author = {Hadley Wickham},
+ journal = {Journal of Statistical Software},
+ year = {2011},
+ volume = {40},
+ number = {1},
+ pages = {1--29},
+ url = {http://www.jstatsoft.org/v40/i01/},
+ }
+ @Manual{readr,
+ title = {readr: Read Tabular Data},
+ author = {Hadley Wickham and Jim Hester and Romain Francois},
+ year = {2016},
+ note = {R package version 1.0.0},
+ url = {https://CRAN.R-project.org/package=readr},
+ }
+ @Manual{readxl,
+ title = {readxl: Read Excel Files},
+ author = {Hadley Wickham and Jennifer Bryan},
+ year = {2017},
+ note = {R package version 1.0.0},
+ url = {https://CRAN.R-project.org/package=readxl},
+ }
+ @Article{reshape2,
+ title = {Reshaping Data with the {reshape} Package},
+ author = {Hadley Wickham},
+ journal = {Journal of Statistical Software},
+ year = {2007},
+ volume = {21},
+ number = {12},
+ pages = {1--20},
+ url = {http://www.jstatsoft.org/v21/i12/},
+ }
+ @Manual{rio,
+ title = {rio: A Swiss-army knife for data file I/O},
+ author = {Chung-hong Chan and Geoffrey CH Chan and Thomas J. Leeper and Jason Becker},
+ year = {2016},
+ note = {R package version 0.4.16},
+ }
+ @Manual{rmarkdown,
+ title = {rmarkdown: Dynamic Documents for R},
+ author = {JJ Allaire and Yihui Xie and Jonathan McPherson and Javier Luraschi and Kevin Ushey and Aron Atkins and Hadley Wickham and Joe Cheng and Winston Chang and Richard Iannone},
+ year = {2020},
+ note = {R package version 2.1},
+ url = {https://github.com/rstudio/rmarkdown},
+ }
+ @Book{rmarkdownBook,
+ title = {R Markdown: The Definitive Guide},
+ author = {Yihui Xie and J.J. Allaire and Garrett Grolemund},
+ publisher = {Chapman and Hall/CRC},
+ address = {Boca Raton, Florida},
+ year = {2018},
+ note = {ISBN 9781138359338},
+ url = {https://bookdown.org/yihui/rmarkdown},
+ }
+ @Manual{rtweet,
+ title = {rtweet: Collecting Twitter Data},
+ author = {Michael W. Kearney},
+ year = {2018},
+ note = {R package version 0.6.7},
+ url = {https://cran.r-project.org/package=rtweet},
+ }
+
+ @Article{sandwich,
+ title = {Object-Oriented Computation of Sandwich Estimators},
+ author = {Achim Zeileis},
+ journal = {Journal of Statistical Software},
+ year = {2006},
+ volume = {16},
+ number = {9},
+ pages = {1--16},
+ url = {http://www.jstatsoft.org/v16/i09/.},
+ }
+
+ @Manual{rgdal,
+ title = {rgdal: Bindings for the Geospatial Data Abstraction Library},
+ author = {Roger Bivand and Tim Keitt and Barry Rowlingson},
+ year = {2016},
+ note = {R package version 1.1-10},
+ url = {https://CRAN.R-project.org/package=rgdal},
+ }
+
+ @Manual{rgeos,
+ title = {rgeos: Interface to Geometry Engine - Open Source (GEOS)},
+ author = {Roger Bivand and Colin Rundel},
+ year = {2016},
+ note = {R package version 0.3-19},
+ url = {https://CRAN.R-project.org/package=rgeos},
+ }
+ @Manual{skimr,
+ title = {skimr: skimr},
+ author = {Eduardo {Arino de la Rubia} and Hao Zhu and Shannon Ellis and Elin Waring and Michael Quinn},
+ year = {2017},
+ note = {R package version 1.0},
+ url = {https://github.com/ropenscilabs/skimr},
+ }
+ @Manual{stringr,
+ title = {stringr: Simple, Consistent Wrappers for Common String Operations},
+ author = {Hadley Wickham},
+ year = {2016},
+ note = {R package version 1.1.0},
+ url = {https://CRAN.R-project.org/package=stringr},
+ }
+ @Manual{@sparklyr,
+ title = {sparklyr: R Interface to Apache Spark},
+ author = {Javier Luraschi and Kevin Ushey and JJ Allaire and {The Apache Software Foundation}},
+ year = {2016},
+ note = {R package version 0.4},
+ url = {https://CRAN.R-project.org/package=sparklyr},
+ }
+
+ @Manual{stargazer,
+ title = {stargazer: Well-Formatted Regression and Summary Statistics Tables},
+ author = {Marek Hlavac},
+ year = {2015},
+ note = {R package version 5.2},
+ organization = {Harvard University},
+ address = {Cambridge, USA},
+ url = {http://CRAN.R-project.org/package=stargazer},
+ }
+
+@article{survey,
+ title = {Analysis of complex survey samples},
+ volume = {9},
+ number = {1},
+ urldate = {}},
+ journal = {Journal of Statistical Software},
+ author = {Lumley, T},
+ pages = {1-19}
+}
+
+ @Manual{tables,
+ title = {tables: Formula-Driven Table Generation},
+ author = {Duncan Murdoch},
+ year = {2017},
+ note = {R package version 0.8},
+ url = {https://CRAN.R-project.org/package=tables},
+ }
+
+ @Manual{tidyverse,
+ title = {tidyverse: Easily Install and Load 'Tidyverse' Packages},
+ author = {Hadley Wickham},
+ year = {2017},
+ note = {R package version 1.1.1},
+ url = {https://CRAN.R-project.org/package=tidyverse},
+ }
+
+ @Manual{twitteR,
+ title = {twitteR: R Based Twitter Client},
+ author = {Jeff Gentry},
+ note = {R package version 1.1.9},
+ url = {http://lists.hexdump.org/listinfo.cgi/twitter-users-hexdump.org},
+ }
+@Manual{viridis,
+ title = {viridis: Default Color Maps from 'matplotlib'},
+ author = {Simon Garnier},
+ year = {2018},
+ note = {R package version 0.5.1},
+ url = {https://CRAN.R-project.org/package=viridis},
+ }
+@Manual{xlsx,
+ title = {xlsx: Read, write, format Excel 2007 and Excel 97/2000/XP/2003 files},
+ author = {Adrian A. Dragulescu},
+ year = {2014},
+ note = {R package version 0.5.7},
+ url = {https://CRAN.R-project.org/package=xlsx},
+ }
+
+@article{zoo,
+ title = {zoo: S3 Infrastructure for Regular and Irregular Time Series},
+ author = {Achim Zeileis and Gabor Grothendieck},
+ journal = {Journal of Statistical Software},
+ year = {2005},
+ volume = {14},
+ number = {6},
+ pages = {1--27},
+ doi = {10.18637/jss.v014.i06},
+ }