Help with SGML errors

[J Horacio MG]

First off, my apologies for the long output.  If this is not the right
place to ask this question, could you point me to the right list?

I'm writing a SGML document and I'm getting some errors when converting
to HTML, LATEX, LYX,... (same errors with all of them):

/usr/bin/nsgmls:<OSFD>0:6:10:E: no start tag specified for implied empty
element "NAME"
/usr/bin/nsgmls:<OSFD>0:7:5:E: document type does not allow element
"DATE" here
/usr/bin/nsgmls:<OSFD>0:8:9:E: document type does not allow element
"ABSTRACT" here
/usr/bin/nsgmls:<OSFD>0:10:4:E: document type does not allow element
"TOC" here

The HTMLized output seems ok, though.  These are the tags I'm using:

----- start doc.sgml -----
<!doctype linuxdoc system>

<article>

<title>any title

<author><p>author1 <tt/<url url="mailto:[EMAIL PROTECTED]" name="&lt;[EMAIL 
PROTECTED]&gt;">/ <p>author2 <tt/url usl="mailto:[EMAIL PROTECTED]" 
name="&lt;[EMAIL PROTECTED]&gt;">/
<date>v0.x May 1999

<abstract/place any text here/

<toc>
----- end doc.sgml -----

If I supress the <p> tags everything works fine, but then I get the
different authors names in one line.  I tried with the html <br> tag,
but that didn't work either.  I also tried writing three different
<author> tags for the different authors, and it work but:

/usr/bin/nsgmls:<OSFD>0:7:7:E: document type does not allow element
"AUTHOR" here
/usr/bin/nsgmls:<OSFD>0:8:7:E: document type does not allow element
"AUTHOR" here

Is there a "clean" way of doing this?

TIA
-- 
Horacio
[EMAIL PROTECTED]
Valencia - ESPAÑA