I will add my support to Arthur and go one further:
The idea that reference/sample implementations require licences i find abhorrent.
If it was truly a _reference_ implementation, that is, one whose behavior *defines*
the standard, that would make sense. But SRFI implementations are just exemplary:
they prove an implementation is possible at all.
SRFIs are a kind of community standards process.
Reference implementations are a vital part of that process.
Copyright may technically be applicable, but licencing should have no part in it.
If there's no license, there's no right to reuse at all: you can read the implementation,
but you can't copy it into your program. That's the plain fact of the
matter. Arthur's right that the existing license applies to the software, which
means that if it incorporates anyone else's software (as many of mine do)
that incorporated code had better be under a permissive open source license.
It has been so far, fortunately, because it's mostly coming from other SRFIs.
But that won't always be true.
--
The present impossibility of giving a scientific explanation is no proof
that there is no scientific explanation. The unexplained is not to be
identified with the unexplainable, and the strange and extraordinary
nature of a fact is not a justification for attributing it to powers
above nature. --The Catholic Encyclopedia, s.v. "telepathy" (1913)