GNU Free Documentation License

                   Version 1.1, March 2000

 Copyright (C) 2000  Free Software Foundation, Inc.

     51 Franklin St, 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.

0. 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.

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 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.

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.

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 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.

4. 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:

A. 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.

B. 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).

C. State on the Title page the name of the publisher of the

   Modified Version, as the publisher.

D. Preserve all the copyright notices of the Document.

E. Add an appropriate copyright notice for your modifications

   adjacent to the other copyright notices.

F. 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.

G. Preserve in that license notice the full lists of Invariant Sections

   and required Cover Texts given in the Document's license notice.

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, 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.

J. 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.

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 acknowledgements

   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 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.

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

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."

6. 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.

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.

8. 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.

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.

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

https://www.gnu.org/licenses/.

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

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.