245 1 4 $aThe big one /$c[John Smith ... et al.].
This is wrong:
245 1 4 $aThe big one /c[John Smith ... [et al.]].
It is a tautology to have a square bracket inside a square bracket.
However:-
830 # 0 $a Research report (Cooperative Research Centre for Coal in Sustainable Development (Australia)) ; ‡v 42.
ALSO
correct
260 # # $a Suva [Fiji]
wrong
260 # # $a Suva, [Fiji] ie no comma
ALSO
correct
260 # # $a [Hobart, Tas. : $b Victoria Rigney], $c c2008.
Example from MARC standards: 260 ##$a[S.l. :$bs.n.,$c15--?]
wrong
260 # # $a [Hobart, Tas.] : $b [Victoria Rigney], $c c2008.
500 Do not use [ ] unless it is inside a quote i.e. " quoted words [ not quoted ] more quoted words"--T.p. verso.