Humanistic–existential and solution-focused approaches to psychotherapy
The chapter "presents evidence-based research in humanistic–existential therapy" including GT
Case formulation in emotion-focused therapy
Research methods (case formularion) about EFT. GT is explicitly mentioned.
The predicted future of psychotherapy: A decennial e-Delphi poll
A Delphi study that foresees that GT will DECREASE its influence in the upcoming years.
Outcomes of beginning trainee therapists in an outpatient community clinic
A study about humanistic approaches that includes GT and concludes that "There were no differences between therapeutic approaches"
Bridging religion and spirituality with gestalt psychotherapy to improve clinical symptoms: Preliminary findings using gestalt pastoral care
Enara - revised. I changed category from RCT to naturalistic study because, despite having a large sample >300 participants, it does not have a control group
Chairwork in individual psychotherapy: Meta-analyses of intervention effects
This is research about chairwork that doesn't mention GT explicitly in the abstract. Maybe it does in the full paper.
Enara - It does.