Mark Dönszelmann, Patrick Hellwig, Tony Johnson, Paolo Palazzi and Mario Ruggier, "YaPPI - Yet another Particle Property Interface", A Particle Property Database, 2001.
Patrick Hellwig, "Particle Properties in XML", Overview, 2000.
Patrick Hellwig, "Particle Properties in XML", Student Session, 2000.
Patrick Hellwig, "YaPPI, An XML Particle Property Database", API Group Meeting Presentation, 2000.