Name	Info	Provider	Link
	subscription/membership/fee required	Atypon	https://www.pnas.org/doi/10.1073/pnas.2026719118?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub 0pubmed
Full text from DIGITALCSIC	free resource	Digital CSIC Spanish National Research Council	http://hdl.handle.net/10261/266029
	free resource	PubMed Central	https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/34417311/
	free resource	Europe PubMed Central	https://europepmc.org/abstract/MED/34417311