Is our contemporary sale of chometz a legal loophole/subterfuge? Should we sell actual chometz (chometz gamur)? 
Mareh Mekomos: 
Tosefta Pesachim 2:6
Pesachim 21a
Chiddushei haRitva Pesachim 21a ד"ה ומוכר
Beis Yosef OC 448:5
Terumas haDeshen 1:120
Gittin 20a
Mishna Berura 448:12
Bechor Shor Pesachim 21a
Teshuvos Chasam Sofer OC 62
Pesachim 4b 
Tosfos, Pesachim 4b, DH מדאורייתא בביטול בעלמא סגי 
Chiddushei haRamban, Pesachim 4b 
Shabbos 139b
Mekor Chaim OC 448:11
Gur Aryeh (Maharal), Bereshis 46:10
Emes L'Yaakov (Baal Nesivos) Brachos 8b
Pe'er haDor (Biography of the Chazon Ish) (ח"ג עמ' רמ"א) 
Minchas Chinuch, mitzvah 112, os beis