div class=trans-pagebutton class=gotoPage data-page=1Page 1button div class=trans-imageimg data-url=document-data-sources-and-time-periods-all-collections-are-divided-into-3-time-periodshtmlpage=1 data-page=1 class=trans-thumb lazyload alt=Page 1: imageslibrarywisceduimageslibrarywisceduEcoNatResEFacsDNRBullData Sources and Time Periods All collections are divided into 3 time periods: 1900-31 1959-74 and 1975-81 loading=lazy src=data:imagegifbase64iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mM8Uw8AAh0BTZud3BwAAAAASUVORK5CYII= data-src=https:reader033fdocumentsnetreader033viewer20220422115eb42f7c4126221f114cbccehtml5thumbnails1jpg width=140 height=200 divdivdiv class=trans-pagebutton class=gotoPage data-page=2Page 2button div class=trans-imageimg data-url=document-data-sources-and-time-periods-all-collections-are-divided-into-3-time-periodshtmlpage=2 data-page=2 class=trans-thumb lazyload alt=Page 2: imageslibrarywisceduimageslibrarywisceduEcoNatResEFacsDNRBullData Sources and Time Periods All collections are divided into 3 time periods: 1900-31 1959-74 and 1975-81 loading=lazy src=data:imagegifbase64iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mM8Uw8AAh0BTZud3BwAAAAASUVORK5CYII= data-src=https:reader033fdocumentsnetreader033viewer20220422115eb42f7c4126221f114cbccehtml5thumbnails2jpg width=140 height=200 divdivdiv class=trans-pagebutton class=gotoPage data-page=3Page 3button div class=trans-imageimg data-url=document-data-sources-and-time-periods-all-collections-are-divided-into-3-time-periodshtmlpage=3 data-page=3 class=trans-thumb lazyload alt=Page 3: imageslibrarywisceduimageslibrarywisceduEcoNatResEFacsDNRBullData Sources and Time Periods All collections are divided into 3 time periods: 1900-31 1959-74 and 1975-81 loading=lazy src=data:imagegifbase64iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mM8Uw8AAh0BTZud3BwAAAAASUVORK5CYII=...