Last week ("The fuel of the future", April 6th) we mistakenly referred to Argus Biomass Markets as the Argus Biomass Report. Worse, we muddled our numbers. The index of wood-pellet prices published by Argus Biomass Markets actually rose from an average of €116 ($152) a tonne, not $116 a tonne, in August 2010 to €129 (not $129) a tonne at the end of 2012. These are the delivered prices into the ports of Amsterdam, Rotterdam and Antwerp.

And in "You’ll never work at home" (March 30th) we said that Summly’s iPhone app summarised news articles in 300-400 words. We meant 300-400 characters. Sorry on both counts.