.. _gfdl:

==============================
GNU Free Documentation License
==============================

.. COMMENT: - GNU Project - Free Software Foundation (FSF)

.. COMMENT: LINK REV="made" HREF="mailto:webmasters@gnu.org"

.. COMMENT: section>
            <title>GNU Free Documentation License</title

Version 1.1, March 2000

    Copyright (C) 2000 Free Software Foundation, Inc. 51 Franklin Street,
    Fifth Floor, Boston, MA 02110-1301 USA Everyone is permitted to copy and
    distribute verbatim copies of this license document, but changing it is
    not allowed.

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Preamble
########

The purpose of this License is to make a manual, textbook, or other
written document "free" in the sense of freedom: to assure everyone the
effective freedom to copy and redistribute it, with or without modifying
it, either commercially or noncommercially. Secondarily, this License
preserves for the author and publisher a way to get credit for their
work, while not being considered responsible for modifications made by
others.

This License is a kind of "copyleft", which means that derivative
works of the document must themselves be free in the same sense. It
complements the GNU General Public License, which is a copyleft license
designed for free software.

We have designed this License in order to use it for manuals for
free software, because free software needs free documentation: a free
program should come with manuals providing the same freedoms that the
software does. But this License is not limited to software manuals; it
can be used for any textual work, regardless of subject matter or whether
it is published as a printed book. We recommend this License principally
for works whose purpose is instruction or reference.

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Applicability and Definition
############################

This License applies to any manual or other work that contains a
notice placed by the copyright holder saying it can be distributed under
the terms of this License. The "Document", below, refers to any such
manual or work. Any member of the public is a licensee, and is addressed
as "you".

A "Modified Version" of the Document means any work containing the
Document or a portion of it, either copied verbatim, or with
modifications and/or translated into another language.

A "Secondary Section" is a named appendix or a front-matter section
of the Document that deals exclusively with the relationship of the
publishers or authors of the Document to the Document's overall subject
(or to related matters) and contains nothing that could fall directly
within that overall subject. (For example, if the Document is in part a
textbook of mathematics, a Secondary Section may not explain any
mathematics.) The relationship could be a matter of historical connection
with the subject or with related matters, or of legal, commercial,
philosophical, ethical or political position regarding them.

The "Invariant Sections" are certain Secondary Sections whose
titles are designated, as being those of Invariant Sections, in the
notice that says that the Document is released under this License.

The "Cover Texts" are certain short passages of text that are
listed, as Front-Cover Texts or Back-Cover Texts, in the notice that says
that the Document is released under this License.

A "Transparent" copy of the Document means a machine-readable copy,
represented in a format whose specification is available to the general
public, whose contents can be viewed and edited directly and
straightforwardly with generic text editors or (for images composed of
pixels) generic paint programs or (for drawings) some widely available
drawing editor, and that is suitable for input to text formatters or for
automatic translation to a variety of formats suitable for input to text
formatters. A copy made in an otherwise Transparent file format whose
markup has been designed to thwart or discourage subsequent modification
by readers is not Transparent. A copy that is not "Transparent" is called
"Opaque".

Examples of suitable formats for Transparent copies include plain
ASCII without markup, Texinfo input format, LaTeX input format, SGML or
XML using a publicly available DTD, and standard-conforming simple HTML
designed for human modification. Opaque formats include PostScript, PDF,
proprietary formats that can be read and edited only by proprietary word
processors, SGML or XML for which the DTD and/or processing tools are not
generally available, and the machine-generated HTML produced by some word
processors for output purposes only.

The "Title Page" means, for a printed book, the title page itself,
plus such following pages as are needed to hold, legibly, the material
this License requires to appear in the title page. For works in formats
which do not have any title page as such, "Title Page" means the text
near the most prominent appearance of the work's title, preceding the
beginning of the body of the text.

.. _gfdl-2:

Verbatim Copying
################

You may copy and distribute the Document in any medium, either
commercially or noncommercially, provided that this License, the
copyright notices, and the license notice saying this License applies to
the Document are reproduced in all copies, and that you add no other
conditions whatsoever to those of this License. You may not use technical
measures to obstruct or control the reading or further copying of the
copies you make or distribute. However, you may accept compensation in
exchange for copies. If you distribute a large enough number of copies
you must also follow the conditions in section 3.

You may also lend copies, under the same conditions stated above,
and you may publicly display copies.

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Copying in Quantity
###################

If you publish printed copies of the Document numbering more than
100, and the Document's license notice requires Cover Texts, you must
enclose the copies in covers that carry, clearly and legibly, all these
Cover Texts: Front-Cover Texts on the front cover, and Back-Cover Texts
on the back cover. Both covers must also clearly and legibly identify you
as the publisher of these copies. The front cover must present the full
title with all words of the title equally prominent and visible. You may
add other material on the covers in addition. Copying with changes
limited to the covers, as long as they preserve the title of the Document
and satisfy these conditions, can be treated as verbatim copying in other
respects.

If the required texts for either cover are too voluminous to fit
legibly, you should put the first ones listed (as many as fit reasonably)
on the actual cover, and continue the rest onto adjacent pages.

If you publish or distribute Opaque copies of the Document
numbering more than 100, you must either include a machine-readable
Transparent copy along with each Opaque copy, or state in or with each
Opaque copy a publicly-accessible computer-network location containing a
complete Transparent copy of the Document, free of added material, which
the general network-using public has access to download anonymously at no
charge using public-standard network protocols. If you use the latter
option, you must take reasonably prudent steps, when you begin
distribution of Opaque copies in quantity, to ensure that this
Transparent copy will remain thus accessible at the stated location until
at least one year after the last time you distribute an Opaque copy
(directly or through your agents or retailers) of that edition to the
public.

It is requested, but not required, that you contact the authors of
the Document well before redistributing any large number of copies, to
give them a chance to provide you with an updated version of the
Document.

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Modifications
#############

You may copy and distribute a Modified Version of the Document
under the conditions of sections 2 and 3 above, provided that you release
the Modified Version under precisely this License, with the Modified
Version filling the role of the Document, thus licensing distribution and
modification of the Modified Version to whoever possesses a copy of it.
In addition, you must do these things in the Modified Version:

#. Use in the Title Page (and on the covers, if any) a title
   distinct from that of the Document, and from those of previous
   versions (which should, if there were any, be listed in the History
   section of the Document). You may use the same title as a previous
   version if the original publisher of that version gives
   permission.

#. List on the Title Page, as authors, one or more persons or
   entities responsible for authorship of the modifications in the
   Modified Version, together with at least five of the principal
   authors of the Document (all of its principal authors, if it has less
   than five).

#. State on the Title page the name of the publisher of the
   Modified Version, as the publisher.

#. Preserve all the copyright notices of the Document.

#. Add an appropriate copyright notice for your modifications
   adjacent to the other copyright notices.

#. Include, immediately after the copyright notices, a license
   notice giving the public permission to use the Modified Version under
   the terms of this License, in the form shown in the Addendum
   below.

#. Preserve in that license notice the full lists of Invariant
   Sections and required Cover Texts given in the Document's license
   notice.

#. Include an unaltered copy of this License.

#. Preserve the section entitled "History", and its title, and add
   to it an item stating at least the title, year, new authors, and
   publisher of the Modified Version as given on the Title Page. If
   there is no section entitled "History" in the Document, create one
   stating the title, year, authors, and publisher of the Document as
   given on its Title Page, then add an item describing the Modified
   Version as stated in the previous sentence.

#. Preserve the network location, if any, given in the Document
   for public access to a Transparent copy of the Document, and likewise
   the network locations given in the Document for previous versions it
   was based on. These may be placed in the "History" section. You may
   omit a network location for a work that was published at least four
   years before the Document itself, or if the original publisher of the
   version it refers to gives permission.

#. In any section entitled "Acknowledgements" or "Dedications",
   preserve the section's title, and preserve in the section all the
   substance and tone of each of the contributor acknowledgements and/or
   dedications given therein.

#. Preserve all the Invariant Sections of the Document, unaltered
   in their text and in their titles. Section numbers or the equivalent
   are not considered part of the section titles.

#. Delete any section entitled "Endorsements". Such a section may
   not be included in the Modified Version.

#. Do not retitle any existing section as "Endorsements" or to
   conflict in title with any Invariant Section.

If the Modified Version includes new front-matter sections or
appendices that qualify as Secondary Sections and contain no material
copied from the Document, you may at your option designate some or all of
these sections as invariant. To do this, add their titles to the list of
Invariant Sections in the Modified Version's license notice. These titles
must be distinct from any other section titles.

You may add a section entitled "Endorsements", provided it contains
nothing but endorsements of your Modified Version by various parties--for
example, statements of peer review or that the text has been approved by
an organization as the authoritative definition of a standard.

You may add a passage of up to five words as a Front-Cover Text,
and a passage of up to 25 words as a Back-Cover Text, to the end of the
list of Cover Texts in the Modified Version. Only one passage of
Front-Cover Text and one of Back-Cover Text may be added by (or through
arrangements made by) any one entity. If the Document already includes a
cover text for the same cover, previously added by you or by arrangement
made by the same entity you are acting on behalf of, you may not add
another; but you may replace the old one, on explicit permission from the
previous publisher that added the old one.

The author(s) and publisher(s) of the Document do not by this
License give permission to use their names for publicity for or to assert
or imply endorsement of any Modified Version.

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Combining Documents
###################

You may combine the Document with other documents released under
this License, under the terms defined in section 4 above for modified
versions, provided that you include in the combination all of the
Invariant Sections of all of the original documents, unmodified, and list
them all as Invariant Sections of your combined work in its license
notice.

The combined work need only contain one copy of this License, and
multiple identical Invariant Sections may be replaced with a single copy.
If there are multiple Invariant Sections with the same name but different
contents, make the title of each such section unique by adding at the end
of it, in parentheses, the name of the original author or publisher of
that section if known, or else a unique number. Make the same adjustment
to the section titles in the list of Invariant Sections in the license
notice of the combined work.

In the combination, you must combine any sections entitled
"History" in the various original documents, forming one section entitled
"History"; likewise combine any sections entitled "Acknowledgements", and
any sections entitled "Dedications". You must delete all sections
entitled "Endorsements."

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Collections of Documents
########################

You may make a collection consisting of the Document and other
documents released under this License, and replace the individual copies
of this License in the various documents with a single copy that is
included in the collection, provided that you follow the rules of this
License for verbatim copying of each of the documents in all other
respects.

You may extract a single document from such a collection, and
distribute it individually under this License, provided you insert a copy
of this License into the extracted document, and follow this License in
all other respects regarding verbatim copying of that document.

.. _gfdl-7:

Aggregation with Independent Works
##################################

A compilation of the Document or its derivatives with other
separate and independent documents or works, in or on a volume of a
storage or distribution medium, does not as a whole count as a Modified
Version of the Document, provided no compilation copyright is claimed for
the compilation. Such a compilation is called an "aggregate", and this
License does not apply to the other self-contained works thus compiled
with the Document, on account of their being thus compiled, if they are
not themselves derivative works of the Document.

If the Cover Text requirement of section 3 is applicable to these
copies of the Document, then if the Document is less than one quarter of
the entire aggregate, the Document's Cover Texts may be placed on covers
that surround only the Document within the aggregate. Otherwise they must
appear on covers around the whole aggregate.

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Translation
###########

Translation is considered a kind of modification, so you may
distribute translations of the Document under the terms of section 4.
Replacing Invariant Sections with translations requires special
permission from their copyright holders, but you may include translations
of some or all Invariant Sections in addition to the original versions of
these Invariant Sections. You may include a translation of this License
provided that you also include the original English version of this
License. In case of a disagreement between the translation and the
original English version of this License, the original English version
will prevail.

.. _gfdl-9:

Termination
###########

You may not copy, modify, sublicense, or distribute the Document
except as expressly provided for under this License. Any other attempt to
copy, modify, sublicense or distribute the Document is void, and will
automatically terminate your rights under this License. However, parties
who have received copies, or rights, from you under this License will not
have their licenses terminated so long as such parties remain in full
compliance.

.. _gfdl-10:

Future Revisions of this License
################################

The Free Software Foundation may publish new, revised versions of
the GNU Free Documentation License from time to time. Such new versions
will be similar in spirit to the present version, but may differ in
detail to address new problems or concerns. See
`<http://www.gnu.org/copyleft/>`_.

Each version of the License is given a distinguishing version
number. If the Document specifies that a particular numbered version of
this License "or any later version" applies to it, you have the option of
following the terms and conditions either of that specified version or of
any later version that has been published (not as a draft) by the Free
Software Foundation. If the Document does not specify a version number of
this License, you may choose any version ever published (not as a draft)
by the Free Software Foundation.

.. _gfdl-howto:

How to use this License for your documents
##########################################

To use this License in a document you have written, include a copy
of the License in the document and put the following copyright and
license notices just after the title page:

    Copyright (c) YEAR YOUR NAME. Permission is granted to copy,
    distribute and/or modify this document under the terms of the GNU Free
    Documentation License, Version 1.1 or any later version published by
    the Free Software Foundation; with the Invariant Sections being LIST
    THEIR TITLES, with the Front-Cover Texts being LIST, and with the
    Back-Cover Texts being LIST. A copy of the license is included in the
    section entitled "GNU Free Documentation License".

If you have no Invariant Sections, write "with no Invariant
Sections" instead of saying which ones are invariant. If you have no
Front-Cover Texts, write "no Front-Cover Texts" instead of "Front-Cover
Texts being LIST"; likewise for Back-Cover Texts.

If your document contains nontrivial examples of program code, we
recommend releasing these examples in parallel under your choice of free
software license, such as the GNU General Public License, to permit their
use in free software.