Your analysis shows that 77.34% of the publications occurred after 2015, but your keyword clustering for Phase 1 (1997–2005) only includes 4 keywords and 2 clusters. Doesn’t this suggest that your search strategy may have systematically excluded early research or that your keyword threshold in VOSviewer was set too high, artificially flattening early research trends?
Malaysian authors and institutions dominate your productivity rankings, and you attribute this to Malaysia’s agricultural output. However, you restricted your search to English-language articles in Web of Science. Could this introduce a geographic publication bias, underrepresenting research from non-English-speaking but agriculturally significant regions (e.g., Latin America, Africa, or non-WOS indexed Chinese journals)?
In Table 1, you present journal h-index values without clarifying whether these are the journals’ overall h-indices or topic-specific h-indices calculated only from the 1333 articles in your dataset. If they are overall journal metrics, how do they accurately reflect influence within the niche field of shell-based biofuel valorization?
Your future research directions section emphasizes the need for “integrated biorefinery systems” and “life cycle assessment,” but your own keyword analysis in Phase III already shows these as active research themes. Are your proposed future directions truly novel, or are they simply a restatement of existing trends already captured in your bibliometric results?
