For Payen and Persoz's paper, see:
Payen A, Persoz JF (1833) Mémoire sur la diastase, les principaux produits de ses reactions et leur applications aux arts industriels. Annales de chimie et de physique 53: 73-92

For a protocol for using amylase and invertase in the classroom, see an article published in 'Science in School', 'Two hydrolytic enzymes and an epistemological–historical approach': http://www.scienceinschool.org/2007/issue4/enzymes