anchor.diff:            </dl>
             <dl class='sources_row even'>
               <dt>Source data</dt>
  -            <dd><a href='http://landsat.usgs.gov/' target='_blank'>Landsat 7 ETM+</a></dd>
  +            <dd>Landsat 5 TM, <a href='http://landsat.usgs.gov/' target='_blank'>Landsat 7 ETM+, and Landsat 8 OLI</a></dd>
             </dl>
             <dl class='sources_row'>
               <dt>Frequency of updates</dt>
  
positive.code: 
          <div class='source_summary'>
            <h3 class='overview_title'>Overview</h3>
            <p>This data set measures areas of tree cover loss across all global land (except Antarctica and other Arctic islands) annually at 30 × 30 meter resolution. The data were generated using multispectral satellite imagery from the <a href='http://landsat.usgs.gov/science_L7_cpf.php' target='_blank'>Landsat 7 thematic mapper plus (ETM+)</a> sensor. Over 600,000 Landsat 7 images were compiled and analyzed using Google Earth Engine, a cloud platform for earth observation and data analysis. The clear land surface observations (30 × 30 meter pixels) in the satellite images were assembled chronologically and a supervised learning algorithm was then applied to identify per pixel tree cover loss or gain.</p>
  
  
  
            <p>Tree cover loss is defined as “stand replacement disturbance,” or the complete removal of tree cover canopy at the Landsat pixel scale. Tree cover loss may indicate a number of potential activities, such as timber harvesting, fires or disease, the conversion of natural forest to other land uses, or the crop rotations cycle of tree plantations. </p>
  
            <p class='credits'><strong>Citation:</strong> Hansen, M. C., P. V. Potapov, R. Moore, M. Hancher, S. A. Turubanova, A. Tyukavina, D. Thau, S. V. Stehman, S. J. Goetz, T. R. Loveland, A. Kommareddy, A. Egorov, L. Chini, C. O. Justice, and J. R. G. Townshend. 2013. “High-Resolution Global Maps of 21st-Century Forest Cover Change.” Science 342 (15 November): 850–53.</p>
  
            <p class='credits'><strong>Suggested citations for data as displayed on GFW:</strong> Hansen, M. C., P. V. Potapov, R. Moore, M. Hancher, S. A. Turubanova, A. Tyukavina, D. Thau, S. V. Stehman, S. J. Goetz, T. R. Loveland, A. Kommareddy, A. Egorov, L. Chini, C. O. Justice, and J. R. G. Townshend. 2013. “Hansen/UMD/Google/USGS/NASA Tree Cover Loss and Gain Area.” University of Maryland, Google, USGS, and NASA. Accessed through Global Forest Watch on  [date]. <a href='http://www.globalforestwatch.org' target='_blank'>www.globalforestwatch.org</a>.</p>
  
            <p class='read_more hidden'><em><%= link_to 'Learn more or download data', sources_path %></em></p>
          </div>
  
negative.code:           </dl>
            <dl class='sources_row even'>
              <dt>Date of content</dt>
              <dd>2001–2013</dd>
            </dl>
            <dl class='sources_row'>
              <dt>Tree cover canopy density</dt>
  