Reference books in a spiritual sense can symbolize knowledge or the akashic records.
A personal reference suggests a record of how we live our lives.
Psychological / emotional perspective: To be asking for or receiving a reference is to be seeking some kind of validating process. We need to know we are ‘fit for purpose’.
Material aspects: When we are giving someone else a reference in dreams, we are giving approval to some of our own ideas and beliefs.
If giving references is a normal part of our everyday behaviour, to do so in dreams may suggest we need to question some of our own beliefs.
To be reluctant to give a reference suggests a lack of trust.