The data are provided in standard PLINK .tped and .tfam file formats. These can be easily converted to GenABEL (see their tutorial online - the citation is provided)
in the main text of our paper) or to other formats using other softwares. Refer to the PLINK publication (cited in the paper) and to http://pngu.mgh.harvard.edu/~purcell/plink/
for further information on the format of transposed filsets in PLINK format.