Hello, I'd like to overlay two histograms for comparison. I know that this can be done, in fact I have done it myself several times. But right now I can't neither remember nor find any documentation. Is there anywhere a comprehensible guide for making graphics / plots with R? I know there are plenty of good tutorials, and I have read many of them, but a nice ref card or something similar would be very helpful (I started writing up one myself, but maybe there is somewhere already an existing one). Regards, January -- ------------ January Weiner 3 ---------------------+--------------- Division of Bioinformatics, University of Muenster | Schlo?platz 4 (+49)(251)8321634 | D48149 M?nster http://www.uni-muenster.de/Biologie.Botanik/ebb/ | Germany