I am writing a statement of purpose and want an alternative for "under the guidance of Professor". I has been used many times in the SOP and I want to avoid using it as much as possible. One alternative I can think of it "worked for Professor ..." but I do not know if that is correct (Objection I have: I think university is the employer and not the professor).
Please let me know how this can be rephrased or alternatives for this. Thanks in advance.