diff --git a/.travis.yml b/.travis.yml
index 04daf27..22d9db8 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -41,6 +41,7 @@
     sources: &apt_sources
       - ubuntu-toolchain-r-test
       - llvm-toolchain-trusty
+      - llvm-toolchain-precise-3.7
       - llvm-toolchain-trusty-3.9
       - llvm-toolchain-trusty-4.0
       - llvm-toolchain-trusty-5.0
@@ -152,7 +153,7 @@
           sources: *apt_sources
 
     # Clang 3.9
-    - env: COMPILER=clang++-3.9 HAS_ASAN_64=true HAS_UBSAN_64=true
+    - env: COMPILER=clang++-3.9 # no HAS_ASAN_64=true HAS_UBSAN_64=true - see errors: https://travis-ci.org/onqtam/doctest/jobs/386263910
       addons: &clang39
         apt:
           packages: ["clang-3.9", "valgrind", "g++-multilib", "libc6-dbg", "libc6-dbg:i386", "g++-6"]
@@ -262,12 +263,6 @@
     # static code analysis
     - env: COMPILER=clang++-4.0 STATIC_CODE_ANALYSIS=true
 
-    # Clang 3.7
-    - env: COMPILER=clang++-3.7
-
-    # Clang 3.9
-    - env: COMPILER=clang++-3.9 HAS_ASAN_64=true HAS_UBSAN_64=true
-
     # OSX GCC 6
     - env: COMPILER=g++-6 HAS_ASAN_32=true HAS_UBSAN_32=true HAS_ASAN_64=true HAS_UBSAN_64=true
       compiler: gcc