| Checklist of orchids of Peninsular Malaysia. PT Ong | 23 | 2017 |
| Fly pollination in four Malaysian species of Bulbophyllum (Section Sestochilus)–B. lasianthum, B. lobbii, B. subumbellatum and B. virescens PT Ong, KH Tan Malesian Orchid J 8, 103-110, 2011 | 23 | 2011 |
| The attraction of flowers of Bulbophyllum (Section Sestochilus) to Bactrocera fruit flies (Diptera: Tephritidae) PT Ong, AKW Hee, SL Wee, KH Tan Malesian Orchid Journal 8, 93-102, 2011 | 17 | 2011 |
| Distribution and conservation implications of limestone plant species in Felda Chiku limestone flora, Kelantan, Malaysia R Kiew, AR Ummul-Nazrah, PT Ong, K Imin, AM Aliaa-Athirah, ... Journal of Tropical Forest Science 31 (1), 19-36, 2019 | 16 | 2019 |
| Wild Orchids of Peninsular Malaysia PT Ong Forest Research Institute Malaysia (FRIM) & Ministry of Natural Resources …, 2012 | 16 | 2012 |
| Two new species of Gastrodia from Terengganu, Peninsular Malaysia PT Ong, P O’Byrne Malesian Orchid Journal 10, 7-16, 2012 | 13 | 2012 |
| Limestone treasures, rare plants in Peninsular Malaysia-what they are, where they grow and how to conserve them R Kiew, AR Rafidah, PT Ong, AR Ummul-Nazrah Malaysian Naturalist 71 (1), 32-41, 2017 | 10 | 2017 |
| A revision of Gastrodia in Peninsular Malaysia PT Ong Malesian Orchid Journal 15, 61-76, 2015 | 10 | 2015 |
| Three species of Bulbophyllum section Racemosae pollinated by Drosophila flies PT Ong, KH Tan Malesian Orchid J 9, 45-50, 2012 | 10 | 2012 |
| Flora of Peninsular Malaysia–Vanilloideae PT Ong Malesian Orchid Journal 21, 69-116, 2018 | 6 | 2018 |
| Vatica najibiana (Dipterocarpaceae), a new species from limestone in Peninsular Malaysia AR Ummul-Nazrah, MAM Hairul, I Kamin, R Kiew, PT Ong PhytoKeys, 99, 2018 | 6 | 2018 |
| Conservation status of some orchids in Peninsular Malaysia LC Lu, M Jutta, R Kiew, P O’Byrne, OP Teck Malesian Orchid Journal: Vol. 12 (2013) 12, 133, 2013 | 6 | 2013 |
| The changing flora of Batu Caves, Selangor, Peninsular Malaysia-1890 to 2020. R Kiew, AR Rafidah, NM AIDIL, PT Ong, YH Cheah Malayan Nature Journal 75 (1), 2023 | 5 | 2023 |
| Malaysia Red List: Plants of Peninsular Malaysia WSY Yong, LSL Chua, KH Lau, KSN Fatinah, YH Cheah, TL Yao, ... Part 1. Research Pamphlet 1, 107, 2021 | 5 | 2021 |
| Pinalia in Malesia: Two new species and some allies P O’Byrne, OP Teck, L Gokusing Malesian Orchid Journal 21, 5-29, 2018 | 4 | 2018 |
| The pollination of two Bulbophyllum species. OP Teck Orchid Review 121, 152-155, 2013 | 4 | 2013 |
| Morphology and movement of Bulbophyllum hortorum (Orchidaceae) flowers enable selection of optimal-sized Dacini fruit fly males as pollinators KH Tan, PT Ong, LT Tan Arthropod-Plant Interactions 17 (5), 647-660, 2023 | 1 | 2023 |
| Pulau Tioman, a lush tropical paradise revisited MY Chew, LG Saw, PT Ong, MY Siti-Munirah, HM Kamarul, K Imin, ... PROCEEDINGS OF THE CONFERENCE ON FORESTRY AND FOREST PRODUCTS RESEARCH 2013, 3, 2014 | 1 | 2014 |
| Flora of Peninsular Malaysia— OP Teck Malesian Orchid Journal: Vol. 12 (2013) 12, 93, 2013 | 1 | 2013 |
| Three species of Bulbophyllum section Racemosae pollinated by Drosophila flies OP Teck, TK Hong Malesian Orchid Journal 9, 1-6, 2012 | 1 | 2012 |
