On 18 June 2009 at 09:36, Bert Gunter wrote: | -- or Chapter 4 in S PROGRAMMING? (you'll need to determine if it's "reader | friendly") +1 It helped me a lot too back in the day. But I am wondering if there are good current alternatives. Hadley: if you could, please send a summary back to the list. Dirk -- Three out of two people have difficulties with fractions.