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<section id="sec-licenses-gfdl-4" xreflabel="``Modification''">

    <title>Modifications</title>

    <para>You may copy and distribute a Modified Version of the
    Document under the conditions of sections <xref
    linkend="sec-licenses-gfdl-2" /> and <xref
    linkend="sec-licenses-gfdl-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:</para>
    
    <para>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.</para>
    
    <para>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
    fewer than five), unless they release you from this
    requirement.</para>
    
    <para>C. State on the Title page the name of the publisher of the
    Modified Version, as the publisher.</para>
    
    <para>D. Preserve all the copyright notices of the
    Document.</para>
    
    <para>E. Add an appropriate copyright notice for your
    modifications adjacent to the other copyright notices.</para>
    
    <para>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.</para>
    
    <para>G. Preserve in that license notice the full lists of
    Invariant Sections and required Cover Texts given in the
    Document's license notice.</para>
    
    <para>H. Include an unaltered copy of this License.</para>
    
    <para>I. Preserve the section Entitled ``History'', Preserve 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.</para>
    
    <para>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.</para>
    
    <para>K. For any section Entitled ``Acknowledgements'' or
    ``Dedications'', Preserve the Title of the section, and preserve
    in the section all the substance and tone of each of the
    contributor acknowledgements and/or dedications given
    therein.</para>
    
    <para>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.</para>
    
    <para>M. Delete any section Entitled ``Endorsements''.  Such a
    section may not be included in the Modified Version.</para>
    
    <para>N. Do not retitle any existing section to be Entitled
    ``Endorsements'' or to conflict in title with any Invariant
    Section.</para>
    
    <para>O. Preserve any Warranty Disclaimers.</para>
    
    <para>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.</para>
    
    <para>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.</para>
    
    <para>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.</para>
    
    <para>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.</para>
    
</section>