Types of integrating scheme include: correlation, in which teachers of different subjects provide a common referent or theme which, in effect, correlates any two or more subjects; fusion, in which two separate courses ([eg] history and literature) are scheduled into the same block of time; and the curriculum approach consisting of broad pre-planned areas from which the teacher-pupil interaction evolves specific study in terms of the special needs, interests and problems of students.Integrated education may also be used to refer to the integration of different phases of education (primary, secondary, post-secondary, out-of-school, and adult education) as a continuing process.