Did existing literature detail how to elaborate a complete set of processes for the selection of suppliers?

Decision Making in NGOs when selecting suppliers.
This order is about supporting the following: “Decision-making impact in the Flow of Relief in Post-Conflict Areas: The case of NGOs in Gaza”.
The research topic is about procurement in NGOs operating in these post-conflicted areas,
particularly finding out how procurement is according to theories, compare the findings to what is implemented in practice, and try to find ways to improve the existing procedures.
This order will focus on decision processes performed by NGOs when selecting suppliers:
– Did existing literature detail how to elaborate a complete set of processes for the
selection of suppliers?
– Did existing literature propose a tentative set of processes for the selection of
suppliers?
– Did existing literature elaborate a detailed set of decision making procedures?
– And any relevant question.