Head noun: proof
Postmodifier: of payment

Same concepts
http://dbpedia.org/resource/Proof-of-payment

Broader concepts

labelprovenanceconfidence
documentisap:2987670640.581074
statementisap:3379730630.514210
documentationisap:966493580.508547
evidenceisap:2962431570.344983
recordisap:1600155270.177106