The problem in question is in the following sentence:
The lecture was on the parameters used in the calculation(s) of the DAS28, SDAI, and CDAI.
The last three abbreviations stand for individual indexes or scores, which are calculated using some parameters.
My question is, whether the word "calculation(s)" should be singular or plural. This question is applicable in other contexts, but I can not think of one right now.
Please, if there is a name for this problem, comment and I shall edit the question properly.
If possible, point me to some grammar rules. Thank you for any insight.