{* *! version 1.0.0  12may2011}{...}
    {cmd:yw(}{it:Y}{cmd:,}{it:W}{cmd:)}
{p2colset 8 22 26 2}{...}
{p2col: Domain {it:Y}:}integers 1000 to 9999 (but probably 1800 to 2100){p_end}
{p2col: Domain {it:W}:}integers 1 to 52{p_end}
{p2col: Range:}{cmd:%tw} dates 1000w1 to 9999w52
                    (integers -49,920 to 418,079){p_end}
{p2col: Description:}returns the {it:e_w} weekly date (weeks since
               1960w1) corresponding to  year {it:Y}, week {it:W}.{p_end}
{p2colreset}{...}
