Khaisang Rukvanich. (1992) Labour force participation, time allocation and quality of life of the aged in Bangkok Metropolis. National Institute of Development Administration,:ม.ป.ท.Khaisang Rukvanich. 1992. Labour force participation, time allocation and quality of life of the aged in Bangkok Metropolis. ม.ป.ท.:National Institute of Development Administration,;Khaisang Rukvanich. Labour force participation, time allocation and quality of life of the aged in Bangkok Metropolis. ม.ป.ท.:National Institute of Development Administration, 1992. Print.