Hidayat, Wanda Gema P.A. “The Employees Perception Analysis Toward The Operational Expectation and Reality Based on Ishikawa and Spider Plot Methods at PT. Tata Makmur Bersama – Sidoarjo ,Indonesia”. Sigmagri, vol. 3, no. 1, Aug. 2023, pp. 21-29, doi:10.32764/sigmagri.v3i01.904.