It is completely possible that there was a strong bias. With that said, all research has its limits. I think the authors have been very honest to discuss their

It is completely possible that there was a strong bias. With that said, all research has its limits. I think the authors have been very honest to discuss their findings and the limitation of the context - best case scenario someone takes the idea to the next level, worst case scenario we know it's a limited study and not conclusive.