removed duplicates and unused reference

4 jobs for docs_fix_duplicates in 5 minutes and 12 seconds (queued for 1 second)
Status Name Job ID Coverage
  Test
passed test_min #183770

00:02:14

passed test_mpi #183771

00:03:42

passed test_mpi_fftw #183772

00:03:55

passed test_mpi_fftw_hdf5 #183773

00:05:12

57.0%