Table 13.

Top twenty keywords in terms of burst strength.

Ranking	Keyword	Burst	Period
1	Vegetable oils	140.94	1996–2011
2	Esters	139.08	1996–2013
3	Transesterification	134.61	2004–2011
4	Rapeseed oil	123.65	1996–2013
5	Fuel	113.88	2002–2011
6	Diesel fuel	79.85	1996–2012
7	Ethanol	62.82	2008–2013
8	Vegetable oil	59.32	2005–2013
9	Fuels	56.46	2007–2013
10	Circular economy	55.75	2020–2022
11	Methyl esters	53.95	2004–2012
12	Kinetics	51.61	2003–2010
13	Mmethanol	51.42	2007–2012
14	Biofuels	47.27	2011–2013
15	Candida antarctica lipase	41.2	2001–2012
16	Biological hydrogen production	38.29	2004–2014
17	Fuel ethanol	37.45	2007–2013
18	Costs	36.87	2007–2013
19	Supercritical methanol	36.32	2007–2012
20	Corn	34.48	2007–2014