cross(x, y = NULL, funs = c(mean, sd, quantile, n, na),
..., cum = FALSE, margin = 0:2, addmargins = FALSE, useNA
= c("no", "ifany", "always"), propNA = TRUE, revert =
FALSE, method = c("pearson", "kendall", "spearman"),
times = NULL, followup = FALSE, test = FALSE,
test.tabular = test.tabular.auto, test.summarize =
test.summarize.auto, test.survival =
test.survival.logrank, show.test = display.test, plim =
4, show.method = TRUE, label = FALSE)