JOHN GERRING2025-11-03200713 978-0-511-26876-2 eBook (EBL)10 0-511-26876-9 eBook (EBL)13 978-0-521-85928-8 hardbackhttps://dl.ftveti.edu.et/handle/123456789/8125en-USCase Study Research Principles and PracticesBook