diff --git a/IV/Makefile b/IV/Makefile
index 96e268a..9f7bae5 100644
--- a/IV/Makefile
+++ b/IV/Makefile
@@ -1,10 +1,11 @@
+SOURCE ?= lithuania-latest.osm.pbf
 WHERE ?= name='Visinčia' OR name='Šalčia' OR name='Nemunas'
 
 .faux_filter-rivers: .faux_import-osm
 	./db -v where="$(WHERE)" -f aggregate-rivers.sql
 	touch $@
 
-.faux_import-osm: lithuania-latest.osm.pbf .faux.db
+.faux_import-osm: $(SOURCE) .faux.db
 	PGPASSWORD=osm osm2pgsql \
 			   -c --multi-geometry \
 			   -H 127.0.0.1 -d osm -U osm \
@@ -15,5 +16,5 @@ WHERE ?= name='Visinčia' OR name='Šalčia' OR name='Nemunas'
 	./db start
 	touch $@
 
-lithuania-latest.osm.pbf:
-	wget http://download.geofabrik.de/europe/lithuania-latest.osm.pbf
+$(SOURCE):
+	wget http://download.geofabrik.de/europe/$@