<!--- Provide a general summary of the issue in the Title above --> In `metrics.chest_belt`, add citation to proper paper for [RVT function](https://github.com/physiopy/phys2denoise/blob/709f3fd1ceca40e6bab923928eed0d291051fa0e/phys2denoise/metrics/chest_belt.py#L17) ## Detailed Description <!--- Provide a detailed description of the change or addition you are proposing --> ## Context / Motivation <!--- Why is this change important to you? How would you use it? --> <!--- How can it benefit other users? --> ## Possible Implementation <!--- Not obligatory, but suggest an idea for implementing addition or change --> <!--- If you already have worked on the idea, please share a link to the branch in your forked project -->
