Complex sentence: Then we have the unreliable sources, one About.com page, two mentions on UFO sites, one mention on Busika, which appears to be user generated content, and the lastly the page from ESA which does not mention this incident in any way.
Split into simpler sentences: Then we have the unreliable sources, one About.com page, two mentions on UFO sites, one mention on Busika, which appears to be user generated content. Lastly we have the page from ESA which does not mention this incident in any way.