I am working on my second paper (as phd projects) which is an extension of my first paper. For my first paper, I will send it to a journal very soon. As I know acceptance of a paper by a journal is not an easy journey. Therefore, may I need to submit my paper for different journals (not at the same time) until it can find a place. My question is, how can I cite my first paper in my second one. I need to submit them at a very close time. For example, if I submit my first paper in this week (for example) then I may send the second one into two weeks (two weeks after the first one is submitted).
Any help, please?