Currently I am writing my master's graduate thesis. I am confused that which ordering style is more formal in a thesis reference list. For instance, consider the following three reference lists that I took as it is in order:
 M. Fedrizzi, S. Giove Incomplete pairwise comparison and consistency optimization European Journal of Operational Research, 183 (1) (2007), pp. 303–313
 Z.S. Xu Goal programming models for obtaining the priority vector of incomplete fuzzy preference relation International Journal of Approximate Reasoning, 36 (3) (2004), pp. 261–270
 P.T. Harker Alternative modes of questioning in the analytic hierarchy process Mathematical Modelling, 9 (3) (1987), pp. 353–360
Here the reference lists were not written in alphabetical order. Is there a general rule (convenience) for better formatting?