Professor (retired/adjunct), Dept. Earth, Atmos. Planet. Sci., Purdue University

Professor of Mathematics, University of Aveiro

professor of geology - geochronologist, VU University Amsterdam, Leiden University

Düzce University Art and Sciences Faculty, Department of Mathematics

Professor of Mathematics, Concordia College Moorhead

University of Ceara

University of Hail & Mansoura University

Researcher, University of Management and Technology Lahore, Pakistan.

INRiM

Ministry of higher education and scientific research Tunisia