Understanding context is the key for delivering a good UX. And this holds true even for research papers. There's no significant UX research on this but as a general rule, reference and citation style largely depends on the subject matter and the publishing body. Let me give you a few examples here:

1. Harvard Referencing - Author-date or Author-Title or Author page enclosed in parentheses. The (Author-date) style is recommended by American Chemical Society and American Psychological Association. It is primarily used in the sciences and social sciences.

(Author-title) and (Author-page) is recommended by Modern Language Association and is followed mostly in arts and humanities.

2. Citation Order System - You give a number in brackets that corresponds to the number of the source listed in the order in which they appear in the report. For example, [1]. This is mostly used in engineering and IEEE follows it.

For American Institute of Physics, references are also numbered in the text and in the reference list, with numbers repeated throughout the text as needed. We can go on here, but these examples give you the idea.

TL;DR - Follow the conventions used by the publishing body. The intended audience will make sense of it.

Quoting from Wikipedia:

Forms of citations generally subscribe to one of the generally accepted citations systems, such as the Oxford,[3] Harvard, MLA, American Sociological Association (ASA), American Psychological Association (APA), and other citations systems, as their syntactic conventions are widely known and easily interpreted by readers. Each of these citation systems has its respective advantages and disadvantages relative to the trade-offs of being informative (but not too disruptive) and thus are chosen relative to the needs of the type of publication being crafted.

There's no significant UX research on this but as a general rule, reference and citation style largely depends on the subject matter and the publishing body. Let me give you a few examples here:

1. Harvard Referencing - Author-date or Author-Title or Author page enclosed in parentheses. The (Author-date) style is recommended by American Chemical Society and American Psychological Association. It is primarily used in the sciences and social sciences.

(Author-title) and (Author-page) is recommended by Modern Language Association and is followed mostly in arts and humanities.

2. Citation Order System - You give a number in brackets that corresponds to the number of the source listed in the order in which they appear in the report. For example, [1]. This is mostly used in engineering and IEEE follows it.

For American Institute of Physics, references are also numbered in the text and in the reference list, with numbers repeated throughout the text as needed. We can go on here, but these examples give you the idea.

TL;DR - Follow the conventions used by the publishing body. The intended audience will make sense of it.

Quoting from Wikipedia:

Forms of citations generally subscribe to one of the generally accepted citations systems, such as the Oxford,[3] Harvard, MLA, American Sociological Association (ASA), American Psychological Association (APA), and other citations systems, as their syntactic conventions are widely known and easily interpreted by readers. Each of these citation systems has its respective advantages and disadvantages relative to the trade-offs of being informative (but not too disruptive) and thus are chosen relative to the needs of the type of publication being crafted.