PLINKST(ha,hb )
1.p←next(ha);q←next(hb)
2.pre←ha;hc←ha
3.while (p<>nil) AND (q<>nil) do
4.case
5. date(p)< date(q):
6.{u←p;p←next(p);RET(u)}
7. date(p)= date(q):
8.{next(pre)←p;pre←p; p←next(p);u←q;q←next(q);RET(u)}
9. date(p)> date(q):
10.{u←q;q←next(q);RET(u)}
11.end(case)
12.end(while)
13.next(pre)←nil
14.return