[pyan]

Doesn't sound as if Mr Vander Ark has altered that much....about 16%....

Comparing almost identical passages of Mr Vander Ark’s Lexicon with her own work, she denounced his “constant pilfering” and “utter laziness”. “I believe this book constitutes wholesale theft of 17 years of my hard work,” she said. “It adds little if anything by way of commentary; the quality of that commentary is derisory; and it debases what I worked so hard to create.
“What particularly galls me is the lack of quotation marks. If Mr Vander Ark had put quotation marks around everything he had lifted, most of the lexicon would be in quotation marks.”

...her lawyers call the lexicon a “rip-off” that lifts 2,034 of its 2,437 entries straight from her work

Times Online