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+Glossary
+========
+
+-  **cfitsio** (`<http://heasarc.gsfc.nasa.gov/fitsio/>`_)
+
+   Library of C and Fortran subroutines for reading and writing data
+   files in FITS data format.
+
+-  **FITS** (`<http://fits.gsfc.nasa.gov/>`_)
+
+   Flexible Image Transport System.
+
+-  **FTOOLS** (`<http://heasarc.gsfc.nasa.gov/ftools/>`_)
+
+   Collection of utility programs to create, examine, or modify data
+   files in the FITS data format.
+
+-  **GNU** (`<http://www.gnu.org/>`_)
+
+   A free Unix-like operating system.
+
+-  **HEASARC** (`<http://heasarc.gsfc.nasa.gov/>`_)
+
+   High Energy Astrophysics Science Archive Research Centre.
+
+-  **Python** (`<http://www.python.org/>`_)
+
+   Dynamic programming language that is used in a wide variety of
+   application domains.
+