How to select a link href using iterator?

[jianbo]

I have a list of links to extract from a web page, but how do I select the attribute href when I use iterator? Following code always select the first link.

  result = Wombat.crawl do
      base_url provider_urls.url
      path '/'
      articles 'css=.article table.olt td.title', :iterator do 
        title({ css: "a" })
        article_path({xpath: Nokogiri::CSS.xpath_for(".article table.olt td.title a")[0] + '/@href'})
      end
    end

http://stackoverflow.com/questions/30498120/ruby-wombot-select-link-url-attribute-within-iterator