Parapat J. The Existence Of PT Jamsostek In Social Security Services For Participant Time Working Agreements (PKWT) ( Study at PT Jamsostek (Persero) Belawan Branch). JLS [Internet]. 2020Apr.30 [cited 2026Apr.26];2(2):69-78. Available from: https://iocscience.org/ejournal/index.php/JLS/article/view/1619