The phrase "a poster at a" is correct and usable in written English.
It can be used when referring to the location or context of a poster, such as in a specific place or event.
Example: "I saw a poster at a local café advertising the upcoming music festival."
Alternatives: "a sign in a" or "a flyer at a".
(A picture of a poster at a bus stop is here).
The first was from a poster at a hospital in Benghazi.
The lone sign that something terrible once occurred is a poster at a gasoline station saying, "We will never forget".
"The Syrian Army for the sake of the safety of the people," read a poster at a checkpoint where men in camouflage checked cars; one driver appeared to be handing over a bag of lettuce to a soldier.
Fleck says he was so intent on being virtuous and saving himself for marriage that he doesn't remember having any strong sexual stirrings, but he does recall that when he was 12 and won a poster at a county fair, he asked not for the one of Farrah Fawcett but the one of Burt Reynolds.
(My favorite, from a poster at a protest march: "We Can't All Marry Liza Minnelli!") But surely none can match the mad extravagance of "The Lily's Revenge," a scrappy spectacle written by and starring the drag artist Taylor Mac, now splashing across the stage of Here Arts Center in a swirling tide of tattered lime green fishnet, eye shadow and sequins.
During that year, Hébrard also presented a poster at an international conference in Mexico on the origins of life, organised by the International Society for the Study of the Origin of Life (ISSOL).
A poster at an air force base (or an airport, I forget which it is, such is the level in question's complete blandness) has a picture of a forest landscape with the words "Good Old Japan" beneath it, as if it's apologizing for this new Itagaki work representing a moldy bread roll beside the glorious banquet of 2004's astonishing Ninja Gaiden.
The painting, "Nude Woman in a Red Armchair," appeared on a poster at the airport advertising an exhibition on Picasso and modern British art at the Scottish National Gallery of Modern Art in Edinburgh.
In the 1980s, the Irish Development Agency put up a poster at the airport showing a graduation class of University College Dublin, and it said, 'We are the young Europeans'.
I actually presented work at three of these conferences (a poster at the small conference and a talk at both the workshop and the fellowship conference), which was well received.
