diff --git a/Makefile b/Makefile
index 0fe3f9e..00243fa 100644
--- a/Makefile
+++ b/Makefile
@@ -21,7 +21,7 @@ $(HS_FILTERS):
 	ghc --make $@.hs -o $@
 
 $(ASCIIMATH):
-	(cd filters/asciimath; make filter-only)
+	(cd filters/asciimath; cabal update; make filter-only)
 
 clean:
 	rm -f $(OUT)
diff --git a/README.md b/README.md
index b401ca6..931e5ce 100644
--- a/README.md
+++ b/README.md
@@ -18,3 +18,8 @@ easy numbering and referencing.
   bibliography management and citation. See [this part of Pandoc
   README](http://pandoc.org/README.html#citations) as well for more infos on
   this.
+
+
+## Dependencies
+
+* `alex` and `happy`