Update state of effectful programming

thesis.bib

@@ -835,6 +835,16 @@
   year      = {1995}
 }
 
+@article{Sabry98,
+  author    = {Amr Sabry},
+  title     = {What is a Purely Functional Language?},
+  journal   = {J. Funct. Program.},
+  volume    = {8},
+  number    = {1},
+  pages     = {1--22},
+  year      = {1998}
+}
+
 @article{Swierstra08,
   author    = {Wouter Swierstra},
   title     = {Data types {\`{a}} la carte},
@@ -3510,4 +3520,15 @@
   title     = {Abstraction for web programming},
   school    = {The University of Edinburgh, {UK}},
   year      = {2010}
+}
+
+# Functional programming
+@article{Hughes89,
+  author    = {John Hughes},
+  title     = {Why Functional Programming Matters},
+  journal   = {Comput. J.},
+  volume    = {32},
+  number    = {2},
+  pages     = {98--107},
+  year      = {1989}
 }