The standard of RSS 2.0 is stragely enough, archived at the Harvard Law School.

Here's an actal RSS feed from the BBC:

<rss xmlns:media="" xmlns:atom="" version="">  
  <channel> 
    <title>BBC News - Home</title>  
    <link>http://www.bbc.co.uk/news/front_page</link>  
    <description>The latest stories from the Home section of the BBC News web site.</description>  
    <language>en-gb</language>  
    <lastBuildDate>Mon, 25 Apr 2016 19:17:36 GMT</lastBuildDate>  
    <copyright>Copyright: (C) British Broadcasting Corporation, see http://news.bbc.co.uk/2/hi/help/rss/4498287.stm for terms and conditions of reuse.</copyright>  
    <image> 
      <url>http://news.bbcimg.co.uk/nol/shared/img/bbc_news_120x60.gif</url>  
      <title>BBC News - Home</title>  
      <link>http://www.bbc.co.uk/news/front_page</link>  
      <width>120</width>  
      <height>60</height> 
    </image>  
    <ttl>15</ttl>  
    <atom:link href="http://feeds.bbci.co.uk/news/rss.xml" class="attribute-value">http://feeds.bbci.co.uk/news/rss.xml" rel="" type=""/>  
    <item> 
      <title>Republican pact 'desperate' says Trump</title>  
      <description>Donald Trump says a pact formed by his two rivals for the Republican presidential crown is a desperate act, a day before five states cast votes.</description>  
      <link>http://www.bbc.co.uk/news/election-us-2016-36132723#sa-ns_mchannel=rss&amp;ns_source=PublicRSS20-sa</link>  
      <guid isPermaLink="">http://www.bbc.co.uk/news/election-us-2016-36132723</guid>  
      <pubDate>Mon, 25 Apr 2016 16:55:38 GMT</pubDate> 
    </item>  
    <item> 
      <title>Canadian hostage killed in Philippines</title>  
      <description>A Canadian man held captive by Islamist militants for months in the Philippines is killed, in an act Prime Minister Justin Trudeau calls "coldblooded murder".</description>  
      <link>http://www.bbc.co.uk/news/world-asia-36132382#sa-ns_mchannel=rss&amp;ns_source=PublicRSS20-sa</link>  
      <guid isPermaLink="">http://www.bbc.co.uk/news/world-asia-36132382</guid>  
      <pubDate>Mon, 25 Apr 2016 18:50:48 GMT</pubDate> 
    </item>  
    <item> 
      <title>US ex-senator, 90, to marry a man</title>  
      <description>Former US Senator Harris Wofford, 90, prepares to marry a man, 20 years after the death of his wife.</description>  
      <link>http://www.bbc.co.uk/news/world-us-canada-36127215#sa-ns_mchannel=rss&amp;ns_source=PublicRSS20-sa</link>  
      <guid isPermaLink="">http://www.bbc.co.uk/news/world-us-canada-36127215</guid>  
      <pubDate>Mon, 25 Apr 2016 07:00:02 GMT</pubDate> 
    </item>

See? it's pretty much as described, just some extra fields up at the end of the channel for the BBC's logo, and such. Each of the fields is enclosed by these tags to keep them separated.