"Bart has completed a Bachelor's degree in Physical Therapy, and three Master's degrees in Clinical Health Science, Philosophy, and Philosophy of Science and Technology. After starting out as a blogger in 2018, Bart sold his business and has now moved on to functional medicine consulting."
NutrEval test: https://www.gdx.net/product/nutreval-nutritional-test-plasma (again, plainly following the outcome on that test won't give you the advice you need)
Noise pollution study from the WHO, that talks about the most important factors: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5858354/
Decibel meter app: "Sound Meter" (it's a dutch one), but most apps if you search for "decibel" are great.
Study about indoor pollutants re-circulating: https://www.ncbi.nlm.nih.gov/pubmed/30202344
Mouth and nasal breathing in sleep difference: https://www.ncbi.nlm.nih.gov/pubmed/3298509
Critique of Judgment book: https://www.amazon.com/Critique-Power-Judgment-Cambridge-Immanuel-ebook/dp/B00CF0JP9U/