diff --git a/quox.bib b/quox.bib
index f46e25d..5ff3784 100644
--- a/quox.bib
+++ b/quox.bib
@@ -196,6 +196,13 @@
     reasoning, recurrence relations, modal type theory}
 }
 
+@misc{crude,
+  author = {McBride, Conor},
+  title  = {Crude but effective stratification},
+  url    = {https://personal.cis.strath.ac.uk/conor.mcbride/Crude.pdf},
+  note   = {slides}
+}
+
 @article{mugen,
   author = {Hou (Favonia), Kuen-Bang and Angiuli, Carlo and Mullanix, Reed},
   title = {An Order-Theoretic Analysis of Universe Polymorphism},