This article is from the Blues Brothers FAQ, by Glen Pringle firstname.lastname@example.org with numerous contributions by others.
There is a reference in "Moving Pictures" (ISBN 0-552-13463-5).
On page 178:
Azhural raised his staff.
'It's fifteen hundred miles to Ankh-Morpork,' he said.
'We've got three hundred and sixty-three elephants, fifty
carts of forage, the monsoon's about to break and we're
wearing ... we're wearing ... sort of things, like glass,
only dark ... dark glass things on our eyes ...' His
voice trailed off. His brow furrowed, as if he'd just
been listening to his own voice and hadn't understood
The air seemed to glitter.
He saw M'Bu staring at him.
He shrugged. 'Let's go,' he said.
These quotes are Copyright (C) 1990 Terry and Lyn Pratchett.
There are two references in "Soul Music" (ISBN 0-552-14029-5).
On page 36:
... 'You do fried rat?' said Glod. 'Best damn fried rat in the city,' said Gimlet. 'OK. Give me four fried rats.' 'And some dwarf bread,' said Imp. 'And some coke,' said Lias patiently. 'You mean rat heads or rat legs?' 'No. Four fried rats.' 'And some coke.' 'You want ketchup on those rats?' 'No.' 'You _sure_?' 'No ketchup.' 'And some coke.' 'And two hard-boilled eggs,' he said. 'And some coke.' 'And two hard-boiled eggs.' 'And some coke.' ...
... 'We might get caught.' 'He can't stop us. We're on a mission from Glod.' 'Right.' ...