_s3c3(form, ser1, col1, ser2, col2, ser3, col3, nc1, nc2, nc3)
{
        local s, s1, s2, s3;

        /* X series */
        if (numstr(col1) == 1 && nc1 == 1)
        {
                s1 = sprintf("%s", ser1);
        }
        else
        {
                s1 = sprintf("col(%s, %s)", ser1, col1);
        }

        /* Y series */
        if (numstr(col2) == 1 && nc2 == 1)
        {
                s2 = sprintf("%s", ser2);
        }
        else
        {
                s2 = sprintf("col(%s, %s)", ser2, col2);
        }

        /* Z series */
        if (numstr(col3) == 1 && nc3 == 1)
        {
                s3 = sprintf("%s", ser3);
        }
        else
        {
                s3 = sprintf("col(%s, %s)", ser3, col3);
        }

        /* formula */
        s = sprintf("%s(%s, %s, %s)", form, s1, s2, s3);

        return(s);
}