Recently, Dr. Yuh-shan Ho discussed the search methods of the paper "Dynamic analysis of international green behavior from the perspective of the mapping knowledge domain" Li et al. (Environ Sci Pollut Res 26:6087-6098, 2019a). In fact, Ho and co-workers have used the search methods in several papers Ivanović et al. (Scientometrics, 105:145-160, 2015); Monge-Nájera & Ho (Rev Biol Trop 63:1255-1266, 2015); Ho & Hartley (Br J Psychol, 107:768-780, 2016). In order to reply to the comments, this letter supplementarily explains the characteristics, scope, and limitations of search methods. In addition, the letter states that researchers can use improved methods suggested by Dr. Ho in future studies.