Joseph F. answered 03/26/19
Career Consultant - Resumes, Interviews, Professional Development
"Refer to Section 2.3" is correct and actually more clear in this case, because 2 is the primary section. "Subsection 2.3" is not clear for your purpose - although this word indicates that 3 is a subsection of 2, it also is saying that "2 is a subsection of a different primary section".
For example:
Section A (primary section)
Subsection 2.3 (sub-section)
Please let me know if you have any questions!
Joey