1. ASHTON , P. S. 1964 Ecological Studies in the Mixed Dipterocarp Forests of Brunei State Oxford Forestry Memoirs, No. 25
2. Taxonomic notes on Bornean Dipterocarpaceae III;ASHTON;Gardens' Bulletin Singapore,1967
3. Speciation among tropical rain forest trees: some deductions in the light of recent evidence;ASHTON;Biological Journal of the Linnean Society,1969
4. Dipterocarpaceae;ASHTON;Flora Malesiana,1982