Dr. Margareta Griesz-Brisson MD, PhD, a world-renowned neurologist from Germany, warned that face masks cause oxygen deprivation and permanent neurological damage, especially in the developing brains of children.

https://needtoknow.news/2020/11/german-neurologist-says-masks-cause-oxygen-deprivation-and-permanent-brain-damage-especially-in-children/

https://archive.org/details/Carbon-Dioxide-Face-Masks

This is the long version of a study published previously as a short research letter by JAMA Pediatrics. (Walach, H., Weikl, R., Prentice, J., Diemer, A., Traindl, H., Kappes, A., & Hockertz, S. (2021)

https://old.reddit.com/r/conspiracy/comments/l8dab9/multiple_studies_show_the_dangers_of_face_masks/

https://archive.org/download/hiv-aids-fauci-documentary/oxygen-deprivation-torture.pdf