“…According to Eqs. (42), (43) and (45), (46), the number of the unknown trial functions is 33 including the 21 stress coefficients 0σ k , 1σ k , 2σ k3 and the 6 displacement coefficients 0ûk , 0ûk , as well as the 6 rotation coefficients 0φ s , 1φ s , leading to a consistent shell model, see, for example, the consistency property of the displacement-based and stress-based shell theories, in [24,25,31,53,54]. In the next Section, a systematic process will be presented for the reduction in the number of variables.…”