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GFDL - The GNU Free Documentation License
Version 1.1, March 2000
Copyright (c) 2000 Free Software Foundation, Inc. 59 Temple Place,
Suite 330, Boston, MA 02111-1307 USA
Everyone is permitted to copy and distribute verbatim copies of this
license document, but changing it is not allowed.
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 modify-
ing it, either commercially or noncommercially. Secondarily, this Li-
cense 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 comple-
ments the GNU General Public License, which is a copyleft license de-
signed 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 pro-
gram 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.
1. APPLICABILITY AND DEFINITIONS
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 manu-
al or work. Any member of the public is a licensee, and is addressed
A "Modified Version" of the Document means any work containing the Doc-
ument 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 pub-
lishers 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 connec-
tion 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 straight-
forwardly 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 auto-
matic 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 modifica-
tion 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 de-
signed 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.
2. VERBATIM COPYING
You may copy and distribute the Document in any medium, either commer-
cially or noncommercially, provided that this License, the copyright
notices, and the license notice saying this License applies to the Doc-
ument are reproduced in all copies, and that you add no other condi-
tions 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.
3. 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 en-
close 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 legi-
bly, 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 distri-
bution 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.
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 Ver-
sion 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:
A. Use in the Title Page (and on the covers, if any) a title dis-
tinct from that of the Document, and from those of previous ver-
sions (which should, if there were any, be listed in the History
section of the Document). You may use the same title as a pre-
vious version if the original publisher of that version gives
B. List on the Title Page, as authors, one or more persons or enti-
ties responsible for authorship of the modifications in the Mod-
ified Version, together with at least five of the principal au-
thors of the Document (all of its principal authors, if it has
less than five).
C. State on the Title page the name of the publisher of the Modi-
fied Version, as the publisher.
D. Preserve all the copyright notices of the Document.
E. Add an appropriate copyright notice for your modifications adja-
cent to the other copyright notices.
F. Include, immediately after the copyright notices, a license no-
tice giving the public permission to use the Modified Version
under the terms of this License, in the form shown in the Adden-
G. Preserve in that license notice the full lists of Invariant Sec-
tions and required Cover Texts given in the Document's license
H. Include an unaltered copy of this License.
I. 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, cre-
ate 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.
J. Preserve the network location, if any, given in the Document for
public access to a Transparent copy of the Document, and like-
wise 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 permis-
K. 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 acknowledge-
ments and/or dedications given therein.
L. 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.
M. Delete any section entitled "Endorsements." Such a section may
not be included in the Modified Version.
N. Do not retitle any existing section as "Endorsements" or to con-
flict in title with any Invariant Section.
If the Modified Version includes new front-matter sections or appen-
dices 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 par-
ties--for example, statements of peer review or that the text has been
approved by an organization as the authoritative definition of a stan-
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-Cov-
er Text and one of Back-Cover Text may be added by (or through arrange-
ments made by) any one entity. If the Document already includes a cov-
er 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.
5. COMBINING DOCUMENTS
You may combine the Document with other documents released under this
License, under the terms defined in section 4 above for modified ver-
sions, provided that you include in the combination all of the Invari-
ant Sections of all of the original documents, unmodified, and list
them all as Invariant Sections of your combined work in its license no-
The combined work need only contain one copy of this License, and mul-
tiple identical Invariant Sections may be replaced with a single copy.
If there are multiple Invariant Sections with the same name but differ-
ent 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 pub-
lisher 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 sec-
tions entitled "Dedications." You must delete all sections entitled
6. COLLECTIONS OF DOCUMENTS
You may make a collection consisting of the Document and other docu-
ments released under this License, and replace the individual copies of
this License in the various documents with a single copy that is in-
cluded in the collection, provided that you follow the rules of this
License for verbatim copying of each of the documents in all other re-
You may extract a single document from such a collection, and dis-
tribute 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.
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 com-
pilation. Such a compilation is called an "aggregate", and this Li-
cense 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.
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 pro-
vided that you also include the original English version of this Li-
cense. In case of a disagreement between the translation and the orig-
inal English version of this License, the original English version will
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, par-
ties 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.
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 de-
tail to address new problems or concerns. See http://www.gnu.org/copy-
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.
ADDENDUM: 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 rec-
ommend 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.
4th Berkeley Distribution 2001 April 23 GFDL(1)
© 1994 Man-cgi 1.15, Panagiotis Christias <email@example.com>