diff --git a/tz-link.htm b/tz-link.htm
index 367197d..4b832c6 100644
--- a/tz-link.htm
+++ b/tz-link.htm
@@ -34,7 +34,17 @@ It is updated periodically to reflect changes made by political bodies
 to UTC offsets and daylight-saving rules.
 This database (often called <samp>tz</samp> or <samp>zoneinfo</samp>)
 is used by several implementations,
-including BSD, DJGPP, GNU/Linux, HP-UX, IRIX, Solaris, and UnixWare.
+including
+<a href="http://www.linux.org/">GNU/Linux</a>,
+<a href="http://www.freebsd.org/">FreeBSD</a>,
+<a href="http://www.netbsd.org/">NetBSD</a>,
+<a href="http://www.openbsd.org/">OpenBSD</a>,
+<a href="http://www.delorie.com/djgpp/">DJGPP</a>,
+<a href="http://unix.hp.com/operating/">HP-UX</a>,
+<a href="http://www.sgi.com/developers/technology/irix.html">IRIX</a>,
+<a href="http://www.sco.com/products/openserver/">SCO OpenServer</a>,
+<a href="http://www.sun.com/solaris/">Solaris</a>, and
+<a href="http://www.sco.com/unixware/">UnixWare</a>.
 In the <samp>tz</samp> database's
 <a href="ftp://elsie.nci.nih.gov/pub/">FTP distribution</a>,
 the code is in the file <samp>tzcode<var>C</var>.tar.gz</samp>,
@@ -107,9 +117,9 @@ Microsoft Windows 95/98/NT4 program.</li>
 <h2>Other time zone databases</h2>
 <ul>
 <li><a href="http://www.astro.ch/cgi-bin/atlw3/aq.cgi?lang=e">Astrodienst
-Online - Atlas Query</a> is Astrodienst's Web version of Shanks's
+- Atlas Query</a> is Astrodienst's Web version of Shanks's
 excellent time zone history atlases published in both <a
-href="http://astrocom.com/software/ACS_PC_Atlas.htm">computer</a> and <a
+href="http://astrocom.com/software/pcatlas.html">computer</a> and <a
 href="http://astrocom.com/books/xrefa.htm#SHANKS">book</a> form by <a
 href="http://astrocom.com/">Astro Communications Services</a>.</li>
 <li><a href="http://worldtime.com/">WORLDTIME: interactive atlas,
@@ -120,23 +130,22 @@ and public holidays in several hundred cities around the world.</li>
 contains data from the Time Service Department of the US Naval Observatory
 (USNO), used as the source
 for the <samp>usno*</samp> files in the <samp>tz</samp> distribution.</li>
-<li>The USNO Astronomical Applications Department publishes answers to
-<a href="http://aa.usno.navy.mil/AA/faq/">Frequently Asked Questions</a>
-about time zones and daylight saving time.</li>
 <li>The <a href="http://www.iata.org/">International
 Air Transport Association</a>
-publishes the IATA Standard Schedules Information Manual (SSIM),
+publishes the <a href="http://www.iata.org/sked/ssim.htm">Standard
+Schedules Information Manual</a>,
 which gives current time zone rules for
 all the airports served by commercial aviation.</li>
 </ul>
 <h2>Maps</h2>
 <ul>
-<li>The United States Central Intelligence Agency publishes a <a
+<li>The <a href="http://www.odci.gov/">United States Central
+Intelligence Agency (CIA)</a> publishes a <a
 href="http://www.odci.gov/cia/publications/factbook/reference/Low%20res%20PDF/low802700.pdf">time
 zone map</a>; the
 <a href="http://www.lib.utexas.edu/Libs/PCL/Map_collection/world_maps.html">
 Perry-Casta&ntilde;eda Library Map Collection</a>
-of the University of Texas at Austin has on-line copies of
+of the University of Texas at Austin has copies of
 recent editions. 
 The pictorial quality is good,
 but the maps do not indicate summer time,
@@ -145,11 +154,28 @@ and parts of the data are a few years out of date.</li>
 current time</a>
 has several fancy time zone maps; it covers Russia particularly well.
 The maps' pictorial quality is not quite as good as the CIA's
-and (as usual with maps) the maps are not quite up to date.</li>
+but the maps are more up to date.</li>
 <li><a href="http://www.worldtimeserver.com/">World Time Server</a>
 has a separate little outline map for each region of each country that
 currently observes a different time.</li>
 </ul>
+<h2>Time zone boundaries</h2>
+<ul>
+<li>Manifold.net's <a
+href="http://www.manifold.net/download/freemaps.html">Free Maps and
+GIS Data</a> includes a Manifold-format map of world time zone
+boundaries distributed under the <a
+href="http://www.gnu.org/copyleft/gpl.html">GNU General Public License
+(GPL)</a>. The GeoCommunity's <a
+href="http://software.geocomm.com/data/intl_timezones.html">International
+Time Zones</a> publishes the same data in other formats.</li>
+<li>The US Geological Survey's National Atlas of the United States
+publishes the <a href="http://www.nationalatlas.gov/timeznm.html">Time
+Zones of the United States</a> in the public domain.</li>
+<li>The GeoCommunity lists several commercial sources for <a
+href="http://spatialnews.geocomm.com/features/timezones/">International
+Time Zones and Time Zone Data</a>.</li>
+</ul>
 <h2>Daylight saving time concepts and history</h2>
 <ul>
 <li><a href="http://webexhibits.com/daylightsaving/">About Daylight
@@ -173,13 +199,18 @@ records <a href="http://pcdsh01.on.br/DecHV.html"
 hreflang="pt-BR">Brazil's daylight saving time decrees (in
 Portuguese)</a>.</dd>
 <dt>Germany</dt>
-<dd>The National Institute for Science and Technology maintains <a
-href="http://www.ptb.de/english/org/4/43/432/lega.htm">a history of
-German legal time</a>.</dd>
+<dd>The National Institute for Science and Technology maintains the <a
+href="http://www.ptb.de/english/org/4/43/432/lega.htm">Realisation of
+Legal Time in Germany</a>.</dd>
 <dt>Israel</dt>
 <dd>The Ministry of Interior periodically issues <a
 href="ftp://ftp.huji.ac.il/pub/tz/announcements"
 hreflang="he">announcements (in Hebrew)</a>.</dd>
+<dt>Mexico</dt>
+<dd>The Investigation and Analysis Service of the Mexican Library of
+Congress has published a <a
+href="http://www.cddhcu.gob.mx/bibliot/publica/inveyana/polisoc/horver/"
+hreflang="es">history of Mexican local time (in Spanish)</a>.</dd>
 <dt>United Kingdom</dt>
 <dd><a
 href="http://student.cusu.cam.ac.uk/~jsm28/british-time/">History of
@@ -189,6 +220,10 @@ with perhaps the best-documented history of clock adjustments.</dd>
 </ul>
 <h2>Precision timekeeping</h2>
 <ul>
+<li><a
+href="http://literature.agilent.com/litwebbin/purl.cgi?org_id=tmo&amp;pub_id=5965-7984E">The
+Science of Timekeeping</a> is an excellent and thorough introduction
+to the theory and practice of precision timekeeping.</li>
 <li><a href="http://www.eecis.udel.edu/~ntp/">Time Server</a> discusses
 the Network Time Protocol (NTP), used to synchronize clocks of
 Internet hosts.</li>
@@ -199,8 +234,8 @@ answers questions like "What is the difference between GMT and UTC?"</li>
 href="http://sadira.gb.nrao.edu/~rfisher/Ephemerides/times.html">Astronomical
 Times</a> explains more abstruse astronomical time scales like TT, TCG,
 and TDB.</li>
-<li><a href="http://www.jpl.nasa.gov/basics/bsf2-3.htm">Earth
-and Its Reference Systems</a>
+<li><a href="http://www.jpl.nasa.gov/basics/bsf2-3.htm">Basics of
+Space Flight - Reference Systems - Time Conventions</a>
 briefly explains interplanetary space flight timekeeping.</li>
 <li><a href="http://hpiers.obspm.fr/webiers/results/bul/README.html">Bulletins
 of IERS</a> contains official publications of the
@@ -209,11 +244,12 @@ when leap seconds occur.</li>
 <li>The <a
 href="http://clockdev.usno.navy.mil/archives/leapsecs.html">Leap
 Second Discussion List</a> covers <a
-href="http://www.gisdevelopment.net/reference/scie/s_t_41_50.htm#47">McCarthy
-and Klepczynski's proposal to remove leap seconds</a>, currently
-being studied by a <a
-href="http://www.intec.rug.ac.be/Research/Projects/ursi/Commissions.html">URSI
-Commission J</a> working group, and the <a href="http://www.iau.org/">IAU</a>
+href="http://clockdev.usno.navy.mil/cgi-bin/wa.exe?A3=ind00&amp;L=leapsecs&amp;P=28537&amp;E=2&amp;B=------_=_NextPart_000_01C0781C.F015C5B0&amp;N=GPS-Nov99_Innov.pdf&amp;T=application/octet-stream">McCarthy
+and Klepczynski's proposal to remove leap seconds</a>
+(which requires discussion list membership to read).
+This proposal is being studied by the URSI Commission J <a
+href="http://space.mit.edu/URSI/leapsecond.html">Working Group on the
+Leap Second</a>, and the <a href="http://www.iau.org/">IAU</a>
 has plans to report on this proposal by 2003.</li>
 </ul>
 <h2>Time notation</h2>