Rubuta ci gaba ga wannan sakin layi - Zieleniec ya ciyar da mafi yawan aikinsa a matsayin masanin tattalin arziki. Daga 1973 har zuwa faduwar mulkin kwaminisanci
a cikin 1989, ya fara aiki a matsayin mai bincike a Cibiyar Nazarin Bincike a Fasahar Injiniya da Binciken Tattalin Arziki, kuma daga baya a Cibiyar Tattalin Arziki ta Cibiyar Kimiyya ta Czechoslovak. Baya ga bincike a cikin ka'idar tattalin arziki, ya yi aiki a kan matsalolin sauyin tattalin arziki daga tsarin tattalin arziki na tsakiya zuwa tattalin arziki na kasuwa. Binciken "Czechoslovakia a mahaɗan hanyoyi", bisa ga bincikensa, yana da tasiri sosai a kan tattaunawar game da gyaran tattalin arziki bayan 1989.