The Bishop Marmion Resource Center has several books (and one video) by or about Marc Nikkel:

• Why Haven't You Left? Letters from the Sudan, by Marc Nikkel, edited by Grant LeMarquand.
• Land of Promise: Church Growth in a Sudan at War (#1 in the Faith in Sudan series), edited by Andrew Wheeler, two chapters written by Marc Nikkel.
• Gateway to the Heart of Africa: Missionary Pioneers in Sudan (#5 in the Faith in Sudan series), edited by Francesco Pierli, Maria Teresa Ratti, and Andrew C. Wheeler, one chapter written by Marc Nikkel.
• Dinka Christianity: The Origins and Development of Christianity Among the Dinka of Sudan with Special Reference to the Songs of Dinka Christians (#11 in the Faith in Sudan series), by Marc Nikkel.
• The Crosses of Dinka Christians, a video featuring Marc Nikkel