As we know, the definite article “the” indicates that a following noun or noun equivalent is definite or has been previously specified by context or by circumstance, as in “reading the morning paper.” Another use of “the” is, of course, to indicate that a following noun or noun equivalent is a unique or a particular member of its class, as in “the President of the Philippines.”
There are two general styles in the use of “the” for serial listings of definite nouns. The first style is to have each of the definite nouns preceded by the article “the,” as in this sentence: “The tailor, the butcher, the baker, and the candlestick-maker all went on Holy Week vacation.” The second style is to use “the” only once before the first item in the list of definite nouns, as in “The tailor, butcher, baker, and candlestick-maker all went on Holy Week vacation.” In this second style, it is implied and understood that the first “the” applies to all of the items, which then are all presumed to be definite nouns.
Now, in the particular case of names of publications, certain publishers may have a well-established stylistic preference in the use of the definite article “the” for their names. In the case of The New York Times and The Saturday Evening Post, for instance, they specify and prefer that the article “the” always precede the name, and that the first letter of “the” should be always in capital letters at that. This is why when these two publications are listed with other names of publications, we must not miss out on their “The’s,” as in this serial listing: ““She beat the bushes offering her free-lance services to The New York Times, Newsweek, Esquire, The Saturday Evening Post, Look, and Time.” Other publications aren’t as demanding.
In the case of the serial listing your presented, “She beat the bushes offering her free-lance services to Look, the Milwaukee Journal, the Chicago Tribune, the New York News Syndicate, Newsweek, Esquire, and the Saturday Evening Post,” you need to check one by one if any of the listed publications have a stylistic preference for the article “the.” Wikipedia is a good place to find out what those stylistic preferences are. Offhand, I know that Look, Newsweek, and Esquire don’t demand the use of “the” ever. On the other hand, the Milwaukee Journal, Chicago Tribune, and New York News Syndicate don’t demand “The” before their names but when these names are serially listed, they’d rather that “the” precede them. In fact, the writer of the serial sentence you presented appears not to have taken stylistic liberties with the use of “the” at all; on the contrary, she seems to have scrupulously researched the stylistic preferences of those publications in the use of the article “the” before their names (although she missed out capitalizing the "T" in "the Saturday Evening Post).
