00381nam a2200133Ia 4500 220216s9999 xx 000 0 und d Dissanayake A B Economic life span of the rubber tree in smallholdings Rubber Research Institute of Ceylon Quarterly Journal 1968 49-53 Rubber Smallholdings JS 57594 57594 0 0 0 8 MAIN MAIN 2 2021-12-17 Volume 44, Issue 04-Mar 0 2021-12-17 00:00:00 2022-02-16 JS