wei soon pang, guo hou loo, guo jeng tan, mardiana mardan, reynu rajan, & nik ritza kosai.  (2024).  comparative evaluation of early diabetic outcomes in southeast asian patients with type 2 diabetes mellitus undergoing roux-en-y gastric bypass (rygb) verssus sleeve gastrectomy (lsg).  - scientific reports.  1-7. 

mohamed arif hameed sultan, muhamad hud muhamad zin, firdaus hayati, zulkifli md zainuddin, nik ritza kosai, reynu rajan, zainal adwin zainal abidin, dayang corieza febriany.  (2023).  improvement in erectile dysfunction among male obese patient, following bariatric surgery in hospital canselor tuanku muhriz (hukm).  - obesity surgery.  1506-1518. 

david eng yeow gan, nik ritza kosai nik mahmood, jitt aun chuah, firdaus hayati.  (2023).  performance and diagnostic accuracy of scoring systems in adult patients with suspected appendicitis.  - lagenbeck's archives of surgery.  1-9. 

nur izreena ismail, khairul najmi muhammad nawawi, deborah chew chia hsin, kok wei hao, nik ritza kosai nik mahmood, gary lee chong chearn, zhiqin wong, azmi mohd tamil, hazel joseph, raja affendi raja ali.  (2023).  probiotic containing lactobacillus reuteri dsm 17648 as an adjunct treatment for helicobacter pylori infection: a randomized, double- blind, placebo- controlled trial.  - helicobacter.  1-11. 

global surgery, globalsurg collaborative, mustafa mohammed taher, nik ritza kosai, dayang nita abdul aziz, reynu rajan.  (2023).  use of telemedicine for postdischarge assessment of the surgical wound: international cohort study, and systematic review with meta-analysis.  - annals of surgery.  1331-1347. 

alfizah hanafiah, asif sukri, nik ritza kosai, mohamad aznan shuhaili, mustafa mohammed taher & raja affendi raja ali.  (2023).  immunophenotyping of gastritis, gastric ulcer and gastric cancer using a cluster of differentiation (cd) antibody microarray.  - sains malaysiana.  187-197. 

sivesh kk., sheraz rm., pritam s., ewan ag., on behalf of oeasophagogastric anastomosis audit group.  (2020).  the influence of the sars-cov-2 pandemic on esophagogastric cancer services: an international survey of esophagogastric surgeons.  - diseases of the esophagus.  1-12. 

reynu rajan, mohammed sam-aan, nik ritza kosai, mohamad aznan shuhaili, tee sze chee, ajay venkateswaran, kamal mahawar.  (2020).  early outcome of bariatric surgery for the treatment of type 2 diabetes mellitus in super-obese malaysian population.  - journal of minimal access surgery.  47-53. 

globalsurg collaborative (nik ritza kosai, reynu rajan, mustafa mohamed taher, dayang nita abdul aziz).  (2019).  global variation in anastomosis and end colostomy formation following left-sided colorectal resection.  - bjs open.  403-414. 

zahra rashidbenam, mohd hafidzul jasman, pezhman hafez, guan hee tan, eng hong goh, xeng inn fam, christopher chee kong ho, zulkifli md zainuddin, reynu rajan, fatimah mohd nor,mohamad aznan shuhaili, nik ritza kosai, farrah hani imran, min hwei ng.  (2019).  overview of urethral reconstruction by tissue engineering: current strategies, clinical status and future direction.  - tissue engineering and regenerative medicine.  365-384. 

wei soon pang, guo hou loo, guo jeng tan, mardiana mardan, reynu rajan, & nik ritza kosai.  (2024).  comparative evaluation of early diabetic outcomes in southeast asian patients with type 2 diabetes mellitus undergoing roux-en-y gastric bypass (rygb) verssus sleeve gastrectomy (lsg).  - scientific reports.  1-7. 

loo guo hou, guhan muthkumaran, nik ritza kosai.  (2024).  unusual presentation of incarcerated true parahiatal hernia: management of a rare clinical entity.  - cureus.  1-6. 

mohamed arif hameed sultan, muhamad hud muhamad zin, firdaus hayati, zulkifli md zainuddin, nik ritza kosai, reynu rajan, zainal adwin zainal abidin, dayang corieza febriany.  (2023).  improvement in erectile dysfunction among male obese patient, following bariatric surgery in hospital canselor tuanku muhriz (hukm).  - obesity surgery.  1506-1518. 

alfizah hanafiah, asif sukri, nik ritza kosai, mohamad aznan shuhaili, mustafa mohammed taher & raja affendi raja ali.  (2023).  immunophenotyping of gastritis, gastric ulcer and gastric cancer using a cluster of differentiation (cd) antibody microarray.  - sains malaysiana.  187-197. 

loo guo hoo, nadia nafsha baharudin, mohamed arif hameed sultan, reynu rajan, nik ritza kosai, lizawati rasul hamidi.  (2023).  adult idiopathic hypertrophic pyloric stenosis presenting with gastroduodenal intussusception: a rare case report.  - turkish journal of surgery.  377-382. 

hanafiah harunarashid, farrah-hani imran,, nik ritza kosai.  (2017).  minor surgery at a glance.  - .  120. 

antimicrobial stewardship committee hctm ukm.  (2018).  hctm ppukm surgical prophylaxis guide 2018.  - .  73. 

nik ritza kosai nik mahmood.  (2023).  how a balloon can help obese persons lose weight.  - the star.  1-7. 

nik ritza kosai nik mahmood.  (2023).  kitakurang-obesity management programme that helps malaysians live healthier, happier and fuller lives.  - kl happening events.  1-3. 

asif sukri, alfizah hanafiah, nik ritza kosai.  (2023).  cd54, cd55 and cd71 regulate interleukin-8 secretion of helicobacter pylori-infected gastric epithelial cells in strain-dependent manner.  - simposium biologi kebangsaan 2023.  1. 

mza zainuddin, j che hamzah, nr kosai, tc cheng, bastion mlc.  (2023).  nutritional optic neuropathy - bariatric surgery gone wrong.  - 12th conjoint ophthalmology scientific conference.  1-2. 

norlaila mustafa, aznida firzah abdul aziz, nik ritza kosai nik mahmood,norasyikin a wahab,zahara abdul manaf, arimi fitri mat ludin, joyce hong soo synn, mohd helmy mokhtar.  (2023).  cpg management of obesity (2nd edition).  - .  1-122.