Final answer:
The provided materials do not reference Koss et al. (1987), and without additional context, it is not possible to describe their discoveries.
Step-by-step explanation:
The work of Koss et al. (1987) is not specifically referenced in the provided materials. Therefore, it is not possible to give an accurate account of their discoveries without additional context or information. It is important to refer to the correct sources and evidence when discussing academic research to ensure the quality and accuracy of information provided.