Kalsbeek, L. (1975). Contours of a christian philosophy: An introduction to Hermans Dooyeweerd's thought. Wedge Foundation.
Čikaški stil citiranja (17. izdanje)Kalsbeek, L. Contours of a Christian Philosophy: An Introduction to Hermans Dooyeweerd's Thought. Toronto: Wedge Foundation, 1975.
MLA način citiranja (9. izdanje)Kalsbeek, L. Contours of a Christian Philosophy: An Introduction to Hermans Dooyeweerd's Thought. Wedge Foundation, 1975.
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