1. P.O. Abraham, J.W. Blencowe, S.E. Chua, J.B. Gomez, G.F.J. Moir, S.W. Pakianathan, B.C. Sekhar, W.A. Southorn, P.R. Wycherley, Novel stimulants and procedures In the exploitation of Hevea: II. Pilot trial using (2-chloroethyl)-phosphonic acid (Ethephon) and acetylene with various tapping systems. J. Rubb. Res. Inst. Malaya 23, 90 (1971)
2. P.O. Abraham, Recent innovations in exploitation of Hevea. The Planter 57, 631–648 (1981)
3. P.O. Abraham, R.S. Tayler, Tapping of Hevea brasiliensis. Trap. Agric. Trin. 44(1), 1–11 (1967)
4. P.D. Abraham, P.R. Wycherley, S.W. Pakianathan, Stimulation of latex flow in Hevea brasiliensis by 4-amino-3,5,6-trichloropicolinic acid and 2-chloroethane-phosphonic acid. J. Rubb. Res. Inst. Malaya. 20, 291–305 (1968)
5. P.O. Abraham, J.B. Gomez, W.A. Southorn, P.R. Wycherley, A method of stimulation of rubber yield in Hevea brasiliensis. Br. Pat. 1281524 (1972)