Characterisation of the stimulants produced by Lactobacillus helveticus in milk for Propionibacterium freudenreichii Pascal G. Piveteau, John O'Callaghan, Bríd Lyons, Séamus Condon and Timothy M. Cogan Lait, 82 1 (2002) 69-80 DOI: 10.1051/lait:2001006