the New York Philharmonic anddevelopment of American concert music in the 19th century(this is my theme, please research about it, and focus on the theme to do)

Using 3-5 valuable resources in the reference. But you have to use the material which is Philharmonic: A History of New York’s Orchestra by Howard Shanet, then you need use the other two more resources. (the latter at a reputable site, please, and this does not include Wikipedia or other sites with anonymous contributors)