K. Kamau, Simon, Dr. Hannah O. Bula, and James O. Oringo. 2018. “Challenges of Performance Appraisal Implementation and Their Effects on Service Delivery in Public Secondary Schools in Githunguri Sub-County of Kiambu County, Kenya”. American Scientific Research Journal for Engineering, Technology, and Sciences 49 (1):175-91. https://asrjetsjournal.org/index.php/American_Scientific_Journal/article/view/4513.