Humphrey, R. H. (2013). Effective leadership: Theory, cases, and applications. SAGE Publications.
Lincoln, A., & Bush, H. K. (2011). Lincoln in his own time: A biographical chronicle of his life, drawn from recollections, interviews, and memoirs by family, friends, and associates. Iowa City: University of Iowa Press.
Schupack, S. (2012). Indira Gandhi. Tarrytown: Marshall Cavendish.
Steinberg, B. (2014). Women in Power: The Personalities and Leadership Styles of Indira Gandhi, Golda Meir, and Margaret Thatcher. Montreaal: McGill-Queen's University Press.