Internal plr functions
anova.stepplr(object, ...)
cross.imat(imat1, imat2)
get.imat(x, level = NULL)
imat(object, x)
print.plr(x, ...)
print.stepplr(x, ...)
summary.plr(object, ...)
summary.stepplr(object, ...)
term.match(term1, term2, termlist, len)
Mee Young Park and Trevor Hastie (2008) Penalized Logistic Regression for Detecting Gene Interactions