div class=ts-pagebutton class=gotoPage data-page=1Page 1button div class=ts-imagea href=https:reader040vdocumentssitereader040viewer2022020223575068801a28ab0f07b0722bhtml5page1jpg target=_blank img data-url=retrocitationhtmlpage=1 data-page=1 class=ts-thumb lazyload alt=Page 1: Retrocitation loading=lazy src=data:imagegifbase64iVBORw0KGgoAAAANSUhEUgAAAAIAAAACCAQAAADYv8WvAAAAD0lEQVR42mP8X8AwAgiABKBAv+vAXklAAAAAElFTkSuQmCC data-src=https:reader040vdocumentssitereader040viewer2022020223575068801a28ab0f07b0722bhtml5thumbnails1jpg width=140 height=200 adivp© 1989 Nature Publishing Grouppdiv