diff --git a/Makefile b/Makefile
index 881cbd0..0413a46 100644
--- a/Makefile
+++ b/Makefile
@@ -13,11 +13,25 @@ DEP_FILES = $(patsubst %.o,%.d,$(OBJ_FILES))
 SHARED_LIBRARY = lib/libatrip.so
 STATIC_LIBRARY = lib/libatrip.a
 
-lib: ctf
+
+extern: $(EXTERNAL_DEPENDENCIES)
+clean-extern: CLEANING=yes
+clean-extern:
+	rm -vrf extern
+#$(DEP_FILES): extern
+.PHONY: extern
+
+lib: extern
+lib: $(DEP_FILES)
 lib: $(SHARED_LIBRARY) $(STATIC_LIBRARY)
+static: $(STATIC_LIBRARY)
+shared: $(SHARED_LIBRARY)
+.PHONY: lib static shared
 
 include $(DEP_FILES)
 
+
+
 $(SHARED_LIBRARY): $(OBJ_FILES)
 	mkdir -p $(@D)
 	$(CXX) -shared $< $(CXXFLAGS) $(LDFLAGS) -o $@
@@ -38,13 +52,16 @@ $(SOURCES): $(MAIN)
 
 tangle: $(SOURCES)
 
+clean-emacs: CLEANING=yes
 clean-emacs:
 	-rm -v $(SOURCES)
 
+clean: CLEANING=yes
 clean:
 	-rm -v $(OBJ_FILES) $(DEP_FILES)
 
-clean-all: bench-clean clean
+clean-all: CLEANING=yes
+clean-all: bench-clean clean-emacs clean clean-extern
 
 bench: $(BENCH_TARGETS)
 
diff --git a/etc/config/gcc.mk b/etc/config/gcc.mk
index 3939bcd..cac00cb 100644
--- a/etc/config/gcc.mk
+++ b/etc/config/gcc.mk
@@ -16,5 +16,5 @@ LDFLAGS += -L$(SCALAPACK_PATH)/lib -lscalapack
 bench: CXXFLAGS := $(filter-out -fPIC,$(CXXFLAGS))
 bench: LDFLAGS += -Wl,-Bstatic
 bench: LDFLAGS += -Llib/ -latrip
-bench: LDFLAGS += -L$(OPENBLAS_PATH)/lib -lopenblas
 bench: LDFLAGS += -Wl,-Bdynamic
+bench: LDFLAGS += -L$(OPENBLAS_PATH)/lib -lopenblas
diff --git a/etc/make/ctf.mk b/etc/make/ctf.mk
index c3cf285..fec16cc 100644
--- a/etc/make/ctf.mk
+++ b/etc/make/ctf.mk
@@ -1,2 +1,4 @@
 include ./etc/make/ctf_vars.mk
 include ./etc/make/ctf_rules.mk
+
+EXTERNAL_DEPENDENCIES += ctf
diff --git a/shell.nix b/shell.nix
index 4630cd4..d2c7c13 100644
--- a/shell.nix
+++ b/shell.nix
@@ -15,10 +15,13 @@ pkgs.mkShell rec {
     emacs
   ];
 
+  /*
   openblas =  pkgs.openblas.override {
     enableStatic = true;
   };
+  */
 
+  /*
   scalapack = import ./etc/nix/scalapack.nix {
     lib = pkgs.lib;
     stdenv = pkgs.stdenv;
@@ -30,13 +33,14 @@ pkgs.mkShell rec {
     blas = pkgs.blas;
     lapack = pkgs.lapack;
   };
+  */
 
   shellHook = ''
     export LAPACK_PATH=${pkgs.lapack}
     export BLAS_PATH=${pkgs.blas}
-    export OPENBLAS_PATH=${openblas}
-    export SCALAPACK_PATH=${scalapack}
-    export LD_LIBRARY_PATH=${scalapack}/lib:$LD_LIBRARY_PATH
+    export OPENBLAS_PATH=${pkgs.openblas}
+    export SCALAPACK_PATH=${pkgs.scalapack}
+    export LD_LIBRARY_PATH=${pkgs.scalapack}/lib:$LD_LIBRARY_PATH
   '';
 
 }