Merge pull request #36 from jiashuwu89/master

Update Elfin_overview.ipynb

pyspedas_examples/notebooks/Elfin_overview.ipynb

@@ -5,7 +5,7 @@
    "metadata": {},
    "source": [
     "# ELFIN EPD data loading example\n",
-    "This notebook demonstrates how to load elfin state data, l1 and l2 epd data. And how to generate enegy and picth angle spectrogram with l2 data."
+    "This notebook demonstrates how to load elfin state data, l1 and l2 epd data. And how to generate enegy and picth angle spectrogram with l2 data. For a description of the l2 epd data variables, please see the [file](https://data.elfin.ucla.edu/ela/l2/elf_epd_l2_vars.csv)."
    ]
   },
   {