INA, AGUSTINA. 2014. “INFLUENCE OF PLAYGROUP ON THE DEVELOPMENT OF CHILDREN AGED 4-6 YEARS OF WORKING MOTHERS (A RETROSPECTIVE COHORT STUDY AT A PRIVATE KINDERGARTEN, KUPANG)”. JURNAL INFO KESEHATAN 12 (1):585-98. http://jurnal.poltekkeskupang.ac.id/index.php/infokes/article/view/42.