Here is some tools to help researching dividend stocks. I will use a link to Realty Income (O) as an example for the links below.
http://dailytradealert.com/dividend-champions-contenders-and-challengers has David Fish’s Dividend Champions, Contenders and Challengers. This is a list of stocks and how long they have been paying a consistent and increasing dividend.
These sites provide a history of dividend.
https://www.dividendchannel.com/history/?symbol=o show a table and graph of the dividend history back to 1995. They include stock splits.
http://www.nasdaq.com/symbol/o/dividend-history is my second pick for looking at dividend history. They do not appear to include stock splits and show a little bit different data.
https://finance.yahoo.com/quote/O/profile?p=o gives a quick overview of the company.
https://finance.yahoo.com/quote/O/financials?p=O is a good place to get the last 3 years or 4 quarters of company financials.
http://data.cnbc.com/quotes/O/tab/5 shows graphically the earnings quarterly and annually. This is helpful to determine if the earnings are trending up or down.
DividendStocksOnline.com is a resource for researching dividend paying stocks.
Disclosure: I own Realty Income (O)