diff --git a/eo/tutorial/Lesson4/Makefile b/eo/tutorial/Lesson4/Makefile
index 628c7222d..9a02e0713 100644
--- a/eo/tutorial/Lesson4/Makefile
+++ b/eo/tutorial/Lesson4/Makefile
@@ -1,4 +1,4 @@
-.cpp: ; c++  -DPACKAGE=\"eo\" -DVERSION=\"0.9.1\" -I. -I../../src -Wall -g  -o $@  $*.cpp ../../src/utils/libeoutils.a ../../src/libeo.a
+.cpp: ; c++  -DPACKAGE=\"eo\" -DVERSION=\"0.9.1\" -I. -I../../src -Wall -g  -o $@  $*.cpp ../../src/es/libes.a ../../src/utils/libeoutils.a ../../src/libeo.a
 
 .cpp.o: ; c++ -DPACKAGE=\"eo\" -DVERSION=\"0.9.1\" -I. -I../../src -Wall -g -c $*.cpp