Nichigai Associates, 1986
Buku Referensi
Berita Pub. SDN.BHD, 1986
Buku Teks
Bangkok : Population Division,ESCAP, 1986, 1986
Buku Referensi
edited by Lewis M. Alexander
University of Rhode Island, 1971
Buku Teks
edited by Lewis M. Alexander
University of Rhode Island, 1968
Buku Teks