kday_onbefore
kday = kday_onbefore(dow, rd - 1); /* Sec.(1.12), Eq.(1.67) */
kday = kday_onbefore(dow, rd + 7); /* Sec.(1.12), Eq.(1.68) */
return kday_onbefore(dow, rd + 7);
return kday_onbefore(dow, rd + 3);
int kday_onbefore(int dow, int rd);