<Journal class="Journal" value="Science" /> <Page class="#txt" value="114"> <Page-2 class="#txt" value="117" /> </Page> <Volume class="#txt" value="252" /> <Year class="Year" value="1991" /> </Reference> <Author class="Author" value="Weber JM" /> <Author class="Author" value="Leung JO" /> <Author class="Author" value="Swanson SJ" /> <Author class="Author" value="Idler KB" /> <Author class="Author" value="McAlpine JB" /> <Medline class="Medline" value="2011746" /> </Paper>