
After further research :
uk.answers.yahoo.com/question/index?qid=20080610050757AAv3H2x
( ,
Wed 8 Jun 2011, 18:21,
archived)
uk.answers.yahoo.com/question/index?qid=20080610050757AAv3H2x

However in the Asterix books it was always "Rsssprrr"
( ,
Wed 8 Jun 2011, 18:46,
archived)