Before revision:  This work proposes the use of the target-side data throughout the back-translation approach to improve both the backward and forward models. We explored using only the target-side monolingual data to improve the backward model through forward translation and the forward model through back-translation.
After revision:  This work proposes a self-training strategy where the output of the backward model is used to improve the backward model through forward translation and the forward model through back-translation.