There is no lack of information from the systems providers, technology solutions and standards options available in the e-invoicing, e-procurement and purchase-to-pay market. Finextra gives great insight to many consultant and market providers ideas about the future in payments, invoices, security and so forth and it is free to join.
From the Finextra site:
Finextra is the leading independent newswire and information source for the worldwide financial technology community.
Finextra covers all significant technology news in wholesale and retail banking, the capital markets and insurance. Finextra also publishes a wide range of research articles, features, white papers and case studies.