diff --git a/.travis.yml b/.travis.yml
index 3b04723..f066c6e 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,8 +1,8 @@
 sudo: false
 language: node_js
 node_js:
-    - "13.6"
-    - "12.14"
-    - "10.16"
+  - "13.9"
+  - "12.14"
+  - "10.16"
 after_success:
-    - "cat ./coverage/lcov.info | ./node_modules/.bin/coveralls"
+  - "cat ./coverage/lcov.info | ./node_modules/.bin/coveralls"
diff --git a/Makefile b/Makefile
index ebf63d5..ecc31c4 100644
--- a/Makefile
+++ b/Makefile
@@ -6,17 +6,17 @@ TYPEDOC:= ./node_modules/.bin/typedoc
 TSC:= ./node_modules/.bin/tsc
 
 test:
-	tsc
+	$(TSC)
 	@NODE_ENV=test $(MOCHA) --trace-warnings --exit -u tdd -R spec
 
 test-cover:
-	tsc
+	$(TSC)
 	echo TRAVIS_JOB_ID $(TRAVIS_JOB_ID)
 	@NODE_ENV=test $(ISTANBUL) $(MOCHAEXEC) --exit --report lcovonly -R spec && \
 	cat ./coverage/lcov.info | $(COVERALLS) || true
 
 cover:
-	tsc
+	$(TSC)
 	@NODE_ENV=test $(ISTANBUL) $(MOCHAEXEC) --exit -R spec ./test/*.js
 
 docs: