1

David L. Loudon & Albert J. Della Bitta (1948:6)

2

James F. Engel, Et. Al. (1968:8)

3

Gerald Zaltman Melanie Wallendorf (1979:6)

4

5

6

Kebutuhan Menurut David McClelland

7

8

9

10

11

12

13

14

15

16

17

18