\sa Unicode whitespace character
doi: 10the literal text doi: 10 (case sensitive) \.the literal . (4610 / 568 / 2E16)
\d{1,50}a Unicode decimal digit, repeated between 1 and 50 times
/the literal / (4710 / 578 / 2F16)
\S+any character that is not Unicode whitespace, repeated at least once
\.the literal . (4610 / 568 / 2E16)
.any Unicode character (except for line terminators)