This doesn't entirely answer your question, but let me point you in the right direction.
In 1997 one pair of the imperf was listed as $110. That was for 1 single pair of them.
Hard to say how much a sheet is worth. Whatever you do, don't tear the sheet apart, and selling pairs, you might end up devaluing it. I'd contact 2 or 3 reputable stamp dealers and have it evaluated. If you don't have stamp dealers in your area look up, on the internet, stamp clubs in your area that might be able to supply you with proper contacts.
Don't simply sell it on eBay or anywhere until you get it valued.
Ten cents.
: The Dreyfus Madonna, c. 1475-1480 : now in the National Gallery, Washington DC : :
The National Gallery is in Trafalgar Square
National Gallery was created in 1824.
National Gallery of Art was created in 1937.
When was the national gallery of victoria built?
"Madonna with Child and Angels" was painted by Filippo Lippi and it is housed in the Uffizi.
Scottish National Gallery was created in 1859.
National Gallery of Canada was created in 1882.
Hungarian National Gallery was created in 1957.
National Gallery of Norway was created in 1842.
National Gallery of Ireland was created in 1864.