- Park, Byeong-Cheol (2010): The search for order and the maintenance of mystery in Old Testament wisdom literature. Stellenbosch.
- Schellenberg, Annette (2007): Qohelet´s Use of the Word ענין: Some Observations on Qoh 1,13; 2,23.26; 3,10, and 8,16. (academia.edu)