Where can i get the budgeting information?

I am doing a project on ‘budgeting’ & i need some articles, documents & even pdf files…etc basically i need anything talking about budgeting. Some basic information will be useful like what is budget? how its being done? its importance?…etc please guide. Thanks
Well its general budgeting, basically for companies only
Please guide me theought budget defination, types,…etc the basics of budgeting, litrature review