P C Aw & A C Ooi
1976 Production statistics for clay sand and rock based industries in Peninsular Malaysia RAK F1 - MX (N) 8/ 1977 - Ipoh Perak Jabatan Penyiasatan Kajibumi Malaysia 1977 - ill:13p. 29.8 cm
1976 Production statistics for clay sand and rock based industries in Peninsular Malaysia RAK F1 - MX (N) 8/ 1977 - Ipoh Perak Jabatan Penyiasatan Kajibumi Malaysia 1977 - ill:13p. 29.8 cm