Chapter 1 | Page 24 In addition, other sources of international jurisprudence and soft law norms on ESC rights developed through the works of the ESCR Committee, Special Rapporteurs and independent experts as well as the works of experts in the field of human rights were also analysed. Other widely recognised international documents such as the Limburg Principles on the Implementation of ICESCR, the Maastricht Guidelines on the Violations of Economic, Social and Cultural Rights, and Maastricht Principles on Extraterritorial Obligations of States in the Area of Economic, Social and Cultural Rights, were also used as key source materials for inferring relevant interpretations in building and supporting the analysis.51 These documents provided a rich source of primary information about the ways in which States interpret, understand and act upon their ESC rights obligations. These data sources therefore served to uncover richer meanings and develop a deeper understanding of the issue under investigation. The data from all these sources were canvassed through document analysis methodology to derive relevant and supporting evidence for the arguments put forward in the thesis. Document analysis is a ‘systematic procedure for reviewing or evaluating documents’.52 It requires data to be rigorously examined and interpreted in order to elicit meaning, and to uncover supporting evidence to further empirical knowledge.53 The procedure involves finding, selecting, appraising and synthesising data contained in documents.54 Such analysis aims to locate data extracts (including excerpts and quotations) that can be organised into 51 The Limburg Principles were advanced by a group of distinguished international experts in internal law in 1986. The Principles have been widely used as forming expert views on the interpretation of the ICESCR norms. They have also been used extensively in national legal systems in relation to violations of ESC rights. The Maastricht Guidelines, which were adopted by a group of more than thirty experts in 1997, build on the Limburg Principles and identify the legal implications of State actions and omissions which lead to violations of ESC rights. While these Principles and Guidelines are non-binding, they are highly regarded as 'soft law norms' of international human rights system. 52 Glenn A Bowen, 'Document Analysis as a Qualitative Research Method' (2009) 9(2) Qualitative Research Journal 27-40, 27. 53 Also see, Juliet Corbin and Anselm Strauss, Basics of Qualitative Research: Techniques and Procedures for Developing Grounded Theory (SAGE Publications, London, 2014). 54 Labuschagne, above n 41; Bowen, above n 52.