Form SC 13D/A EXA CORP Filed by: GAMCO INVESTORS, INC. ET AL Nov 20, 2017 01:33PM
Form SC 13D EXA CORP Filed by: GAMCO INVESTORS, INC. ET AL Oct 26, 2017 10:54AM
Form SC 13D EXA CORP Filed by: GAMCO INVESTORS, INC. ET AL Oct 26, 2017 09:08AM