A Digital Object Identifier (DOI) is a unique alphanumeric string that identifies content and provides a persistent link to its location on the InternetTechnically, a DOI is a registered URI (Uniform Resource Identifier) within the info-URI namespace (IETF RFC 4452)
Most scientific publications nowadays are identified by a DOITo resolve a DOI, one may either go to or directly obtain the URL by appending the DOI to the string

publications  /  DOI