direction of the stability of the packages. A package should only depend upon packages that are more stable than it is. " 1 ύοέʔδͷґଘؔɺ҆ఆੑͷํʹґΒͳ͚ΕͳΒͳ͍ɻ ύοέʔδɺΑΓ҆ఆͨ͠ύοέʔδʹͷΈґଘ͖ͩ͢ɻ ɹɹɹɹɹɹɹɹɹɹɹɹɹɹɹɹɹɹɹɹɹɹɹɹɹɹɹ- Robert C. Martin 1 Stable Dependencies Principle http://wiki.c2.com/?StableDependenciesPrinciple 11