[[Image(IMG_2547_sm.jpg, 40%, title="WO6_Huygens_1724_2 ECHO 12", alt="WO6_Huygens_1724_2 ECHO 12")]]
[http://echo.mpiwg-berlin.mpg.de/ECHOdocuView/ECHOzogiLib?pn=12&ws=1&wx=0.2262&wy=0.3849&ww=0.6958&wh=0.2826&mode=imagepath&url=%2Fmpiwg%2Fonline%2Fpermanent%2Flibrary%2FY97ESDAP%2Fpageimg WO6_Huygens_1724_2 ECHO 12]

[[Image(IMG_2549_sm.jpg, 40%, title="WO6_Huygens_1724_2 ECHO 84", alt="WO6_Huygens_1724_2 ECHO 84")]]
[http://echo.mpiwg-berlin.mpg.de/ECHOdocuView/ECHOzogiLib?pn=84&ws=1&wx=0.0815&wy=0.5184&ww=0.6679&wh=0.3224&mode=imagepath&url=%2Fmpiwg%2Fonline%2Fpermanent%2Flibrary%2FY97ESDAP%2Fpageimg WO6_Huygens_1724_2 ECHO 84]

[[Image(IMG_2553_sm.jpg, 40%, title="WO4_Berzelius_1819 ECHO 241", alt="WO4_Berzelius_1819 ECHO 241")]]
[http://echo.mpiwg-berlin.mpg.de/ECHOdocuView/ECHOzogiLib?pn=241&ws=1&wx=0.0024&wy=0.4715&ww=0.8822&wh=0.446&mode=imagepath&url=%2Fmpiwg%2Fonline%2Fpermanent%2Flibrary%2FWCWY69V2%2Fpageimg WO4_Berzelius_1819 ECHO 241]

[[Image(IMG_2559_sm.jpg, 40%, title="WO1_Pappus_1660 ECHO 29", alt="WO1_Pappus_1660 ECHO 29")]]
[http://echo.mpiwg-berlin.mpg.de/ECHOdocuView/ECHOzogiLib?pn=29&ws=1&wx=0.0344&wy=0.6846&ww=0.7844&wh=0.2315&mode=imagepath&url=%2Fmpiwg%2Fonline%2Fpermanent%2Flibrary%2FA0VHBVNN%2Fpageimg WO1_Pappus_1660 ECHO 29]

[[Image(IMG_2564_sm.jpg, 40%, title="WO1_Pappus_1660 ECHO 56", alt="WO1_Pappus_1660 ECHO 56")]]
[http://echo.mpiwg-berlin.mpg.de/ECHOdocuView/ECHOzogiLib?pn=56&ws=1&wx=0.2141&wy=0.4289&ww=0.7473&wh=0.3536&mode=imagepath&url=%2Fmpiwg%2Fonline%2Fpermanent%2Flibrary%2FA0VHBVNN%2Fpageimg WO1_Pappus_1660 ECHO 56]

[[Image(IMG_2566_sm.jpg, 40%, title="CWOB Taixi shiwu qiyuan ECHO 68", alt="CWOB Taixi shiwu qiyuan ECHO 68")]]
[http://echo.mpiwg-berlin.mpg.de/ECHOdocuView/ECHOzogiLib?url=%2Fmpiwg%2Fonline%2Fpermanent%2Flibrary%2F6NRCED2F%2Fpageimg&mode=imagepath&pn=68 CWOB Taixi shiwu qiyuan ECHO 68]