landlord/tenant laws and lease forms, IL, Cook County

[Yulia J.]

My husband and I are closing on our first 3-flat soon - it's in IL, Cook County (a suburb, not Chicago). We will be living in 1 of the units and renting out the other 2. The 2 units have month-to-month tenants who have been there for years, and they might decide to stay or not. We plan to ask them to sign 9-12 months lease agreements. I am trying to read up and get prepared before the closing date and before we meet them in person. What is the best source to study federal, state and county laws describing landlord/tenant rights and responsibilities? And what is the best source to get lease agreement forms and other necessary forms compliant with state/county laws and regulations? 

I will appreciate any links or references!