The Format of NIfTI Files
The NIfTI file format is described on the page of the National Institutes of Health: https://nifti.nimh.nih.gov/nifti-1/
Example data and software can be downloaded from the NeuroImaging Tools & Resources Collaboratory: https://www.nitrc.org/projects/nifti
Information about the BIDS standard can be found at: https://github.com/bids-standard/