1. Information on https://en.wikipedia.org/wiki/Burundi.
2. Information on http://www.isteebu.bi/index.php/economie-en-bref.
3. Information on: https://en.wikipedia.org/wiki/List_of_African_countries_by_population_density#cite_note-1.
4. N. Faisol, A. R. J. Dainty, and A. D. F. Price, The concept of relational contracting as a tool for understanding inter-organizational relationships in construction, in: F. Khosrowshahi (Ed.), Proceedings 21st Annual ARCOM Conference, SOAS, University of London. Association of Researchers in Construction Management. 2, 7-9 September 2005, pp.1075-1084.
5. Leonas Ustinovichius, Edita Šarkienė, The analysis of apartment house construction investments efficiency applying mathematical modelling, Proceedings of the 5th International Conference RelStat, (2005).