IKPO, Ime Johnson. Variability Analysis of Prime Cost Sums. Civil Engineering Dimension, [S. l.], v. 10, n. 1, p. pp. 40–44, 2008. DOI: 10.9744/ced.10.1.pp. 40-44. Disponível em: https://ced.petra.ac.id/index.php/civ/article/view/16732. Acesso em: 4 oct. 2025.