URL https://www.researchgate.net/profile/Earl-Babcock/publication/233961206/figure/fig8/AS:651164353826832@1532261088200/Diagram-of-our-SEOP-setup-showing-all-the-basic-components-used-for-SEOP-and.png
URL2 https://www.researchgate.net/figure/Diagram-of-our-SEOP-setup-showing-all-the-basic-components-used-for-SEOP-and_fig8_233961206
