diff --git a/References/Feller_2011.pdf b/References/Feller_2011.pdf new file mode 100644 index 0000000..6bf1d2e Binary files /dev/null and b/References/Feller_2011.pdf differ diff --git a/References/Feller_2013.pdf b/References/Feller_2013.pdf new file mode 100644 index 0000000..60a1754 Binary files /dev/null and b/References/Feller_2013.pdf differ diff --git a/References/Feller_2015.pdf b/References/Feller_2015.pdf new file mode 100644 index 0000000..c160c4a Binary files /dev/null and b/References/Feller_2015.pdf differ diff --git a/References/Karton_2007.pdf b/References/Karton_2007.pdf new file mode 100644 index 0000000..01ea064 Binary files /dev/null and b/References/Karton_2007.pdf differ diff --git a/References/Kesharwani_2018.pdf b/References/Kesharwani_2018.pdf new file mode 100644 index 0000000..0566f1a Binary files /dev/null and b/References/Kesharwani_2018.pdf differ diff --git a/References/Martin_1996.pdf b/References/Martin_1996.pdf new file mode 100644 index 0000000..f457265 Binary files /dev/null and b/References/Martin_1996.pdf differ