Your TEXTBOOK also has sources which you can use

1.    Textbook investigation samples for Historical investigation (HI)

More money, more hobbies?” (hobbies in pre-World War 2 Singapore).

Some additional useful sources for Chapter 4

1.    Chinese Textbook pages 165-167 sources 39, 40,41, 42, 43, 44

2.    Malay Textbook pages 179-181 sources 59, 60,61, 62, 63, 64

3.    Indian Textbook pages 168-169 source 46

4.    European Textbook page 161 source 31

5.    Extra sources Textbook pages 147 sources5-8

Textbook pages 173 sources 49-50