If you go to the Scientific America website archives you
should be able to find about a dozen papers that encompass this subject. Another site would be Academia.com but it requires membership and is more for the Scientific Community to publish and get peer reviews.
The link you site tries to show that not only evaporation is affected but also plant respiration (transpiration through the leaves), unfortunately transpiration through leaves is independent of soil moisture levels since all plants but the succulents have stoma that expel moisture along with
CO2 or O2 and wastes.
Mulch layers need to be thicker than one inch to have a noticeable effect on soil moisture loss during warm weather. mulch layers over 8 inches thick will have an adverse effect on plant growth because they will cool the soil below the needed warmth levels that most plant
roots need to operate best.