Waldemar, W., N. Kartika, and S. Muawanah Robial. “PRODUCTIVITY ANALYSIS OF FLOOR HERONING WORKERS USING WORK SAMPLING METHOD”. Jurnal Pensil : Pendidikan Teknik Sipil, Vol. 11, no. 2, May 2022, pp. 162 -70, doi:10.21009/jpensil.v11i2.25474.