"Không" became one of the signature songs of Elvis Phương's singing career, as well as some other Nguyen Anh 9's songs such as "Ai đưa em về" (Who takes you home), "Chia phôi" (Parting), "Một lời cuối cho em" (One last word for you)... frequently performed by Elvis Phương on the stage of Queen Bee discothèque in Saigon in early 1970s.In the early 1970s, Nguyen Anh 9 collaborated with many major discothèques in Saigon.