Answer

A company develops organically over time from the cumulative traits of the people the company hires. Corporate culture is generally not expressly defined.  If it is, the culture stated may not always match the current culture or what it’s actually like to work within the corporation.
One way to search for a company's corporate culture is to search their website and culture. For example search “walmart.com corporate culture” This type of search may result, as in this example, in a careers and core values section of the company site.

On the NYU Business Library's company page,  search Indeed (a recruiting site) for insider information and glimpses into a company's corporate culture.  

Go to the NYU Business Library's Journals/Newspapers section and search for articles in databases including ABI/INFORM or Business Source Complete.

Go to the NYU Business Library's Case Studies section for useful resources including a link to the following suggested resource:

Sage Business Cases:  Provides a digital collection of business cases, search “corporate culture” in the advanced search tab.