diff --git a/References/Booth_2012.pdf b/References/Booth_2012.pdf
new file mode 100644
index 0000000..b136f25
Binary files /dev/null and b/References/Booth_2012.pdf differ
diff --git a/References/Kong_2010.pdf b/References/Kong_2010.pdf
new file mode 100644
index 0000000..ba129ad
Binary files /dev/null and b/References/Kong_2010.pdf differ
diff --git a/References/Kong_2011.pdf b/References/Kong_2011.pdf
new file mode 100644
index 0000000..3156df9
Binary files /dev/null and b/References/Kong_2011.pdf differ
diff --git a/References/Torheyden_2009.pdf b/References/Torheyden_2009.pdf
new file mode 100644
index 0000000..7bdde33
Binary files /dev/null and b/References/Torheyden_2009.pdf differ
diff --git a/References/Wiles_2018.pdf b/References/Wiles_2018.pdf
new file mode 100644
index 0000000..a507cc8
Binary files /dev/null and b/References/Wiles_2018.pdf differ