Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Character(s) | First Appearance | Cover Date | Publisher | Estimated Value |
| --- | --- | --- | --- | --- |
| Superman | Action Comics #1 | June 1938 | DC Comics | $2,100,000 |
| Batman | Detective Comics #27 | May 1939 | DC Comics | $475,000 |
| Sandman (Wesley Dodds) | Adventure Comics #40 | July 1939 | DC Comics | $60,000 |
| Namor the Sub-Mariner | Marvel Comics #1 | October 1939 | Timely Comics | $400,000 |
| Jay Garrick/Flash I ; Hawkman | Flash Comics #1 | January 1940 | All-American Pubs. | $95,000 |
| Captain Marvel | Whiz Comics #2 | February 1940 | Fawcett Comics | $90,000 |
| Robin | Detective Comics #38 | May 1940 | DC Comics | $75,000 |
| The Spectre | More Fun Comics #52 | February 1940 | DC Comics | $72,000 |
| Lex Luthor | Action Comics #23 | May 1940 | DC Comics | $8,025 |
| The Joker ; Catwoman | Batman #1 | Spring 1940 | DC Comics | $160,500 |
| Green Lantern | All-American Comics #16 | July 1940 | All-American Pubs. | $131,250 |
| Captain America | Captain America Comics #1 | March 1941 | Timely Comics | $125,250 |
| Aquaman ; Green Arrow | More Fun Comics #73 | November 1941 | DC Comics | $10,050 |
| Wonder Woman | All Star Comics #8 | December 1941 | All-American Pubs. | $60,000 |
| Barry Allen/Flash II | Showcase #4 | October 1956 | DC Comics | $48,000 |
| The Justice League of America | The Brave and the Bold #28 | May 1960 | DC Comics | $8,127 |
| The Fantastic Four | The Fantastic Four #1 | November 1961 | Marvel Comics | $28,896 |
| The Hulk | The Incredible Hulk #1 | May 1962 | Marvel Comics | $21,672 |
| Dr. Doom | The Fantastic Four #5 | June 1962 | Marvel Comics | $4,154 |
| Spider-Man | Amazing Fantasy #15 | August 1962 | Marvel Comics | $45,150 |
| Iron Man | Tales of Suspense #39 | March 1963 | Marvel Comics | $3,837 |
| Doctor Strange | Strange Tales #110 | July 1963 | Marvel Comics | $3,500 |
| X-Men ; Magneto | X-Men #1 | September 1963 | Marvel Comics | $13,545 |
| The Avengers | The Avengers #1 | September 1963 | Marvel Comics | $5,148 |
| Daredevil | Daredevil #1 | April 1964 | Marvel Comics | $3,160 |
| Teen Titans | The Brave and the Bold #54 | July 1964 | DC Comics | $415 |
| The Punisher | The Amazing Spider-Man #129 | February 1974 | Marvel Comics | $918 |
| Wolverine | The Incredible Hulk #180 | October 1974 | Marvel Comics | $350 |
Question:
 what's the cover date where character(s) is sandman (wesley dodds)
Answer:
July 1939