message: add references for the implementation
diff: @@ -9,9 +9,7 @@ find_package(OpenCV REQUIRED)
  add_executable(heat-equation heat-equation.cpp)
  target_link_libraries(heat-equation Ginkgo::ginkgo ${OpenCV_LIBS})
  -configure_file(../../matrices/examples/gko_logo_2d.mtx data/gko_logo_2d.mtx COPYONLY)
  -configure_file(../../matrices/examples/gko_text_2d.mtx data/gko_text_2d.mtx COPYONLY)
  # Copy the data files to the execution directory
  -configure_file(data/initial.mtx data/initial.mtx COPYONLY)
  -configure_file(data/source.mtx data/source.mtx COPYONLY)
  +configure_file(../../matrices/examples/gko_logo_2d.mtx data/gko_logo_2d.mtx COPYONLY)
  +configure_file(../../matrices/examples/gko_text_2d.mtx data/gko_text_2d.mtx COPYONLY)
  