Vikiru, Lillian. Advancing in English : a new integrated course for secondary schools; student's book 4 / Lillian Vikiru, Hilda Omwoyo, Hilda Oburu. - Nairobi : Longhorn, 2005. - vi, 304 p. ISBN: 996649439 : KES 350 Subjects--Topical Terms: English language --Textbooks.