Leila Jafari and  Viliam Makis and  Akram Khaleghei G.B.,  Optimal Maintenance Policy for a Partially Observable Two-Unit System.   journal   = {International Journal of Mechanical and Mechatronics Engineering}, [online]. World Academy of Science, Engineering and Technology.
    September 2014, vol. 93(9). 1612 - 1619
    [viewed 20 April 2024]. Available from: https://publications.waset.org/pdf/9999428.