The phrase "advertisements by a" is correct and usable in written English.
It can be used when referring to advertisements that are created or published by a specific entity or individual.
Example: "The advertisements by a local bakery have attracted many new customers to the shop."
Alternatives: "ads from a" or "commercials by a".
He has been attacked in radio and television advertisements by a national term-limits group.
The three senators, though, were being praised in weekend radio advertisements by a labor-affiliated advocacy group.
The advertisements by a group of veterans attacking the war record of Mr. Kerry have reopened wounds and frayed some unifying threads.
The song, "Here Comes Mister Softee," was written in 1959 for radio and television advertisements by a Philadelphia firm, Grey Advertising.
Pressed about advertisements by a group called Swift Boat Veterans for Truth, Mr. Bush called "rather compelling" the claims of some veterans who have attacked Mr. Kerry's service, and he noted that others had accused these veterans of lying.
State Republicans attributed the loss to the often scathing advertisements by a wide range of special-interest groups, including advertisements that criticized Mr. Abraham's support for a relaxation of some immigration restrictions.
And his own campaign efforts are being supplemented by mailings, phone banks and radio advertisements by an array of conservative groups bitterly opposed to Mr. McCain.
People respond to its advertisements by ringing a toll-free number and Citibank sends the inquirer a package of information and an application form.
"Say no to government-run health care," a narrator says in the advertisement by a conservative group that particularly went after the idea of a government insurance option.
Visa was unhappy, calling it ambush marketing, even though such attacks usually involve the unexpected appearance of an advertisement by a competitor, like MasterCard or American Express.
But it is a delicate business, one that works best when the option is there and taken up by a table on its own, without advertisement by a server.
