The purpose of academic study is to begin to acquire, and be able to demonstrate, the ability to research and write about organisational topics in an academic way. General web resources may lead you to substantively non-academic sources. In particular, you are likely to find generic encyclopaedic (e.g. wikipedia) ‘information’; other practitioner articles; consultants own /adapted models; other university lecture materials; motivation essays for sale etc. (big plagiarism no-no, obviously!). None of these are appropriate – most lack the necessary theoretical and research content, as well as potentially facilitating/tempting plagiarism (we will be checking anyway).
More importantly, the thing about ‘proper’ journal articles, that sets them apart from the web-based ‘grey literature’ as it is known, is that that they have all gone through a rigorous process of ‘peer- review’. This means that before they are accepted for publication in the journal, other experts in the field have reviewed and given feedback on the articles. So peer-reviewed journal articles are basically verified as academically credible ‘knowledge’. There is a place for all the web-based stuff of course, but not in this piece of degree-level coursework, I’m afraid.
If you are having problems finding material it could be for a number of reasons – is your use of search terms too broad or too narrow? Are you looking back far enough – you can include material from the past ten years or so if necessary? Are you just looking for particular theories or looking more broadly at research studies investigating aspects of motivation, incentives etc.? Have you thought of following up key references in the text books? These can be a good starting point. Once you have found a relevant article you will usually find that it cites other useful references you can follow up – it’s like a snow-ball effect once you get started. Remember that you can also refer to books on motivation (books are peer-reviewed too), and these too will cite potential references to follow-up.
For the purpose of simply outlining the basics of the older motivation theories it is acceptable to use and cite the references for e.g. Maslow that are given in your text book – because these are much older ‘seminal works’, not necessarily easy to get hold of. But there are more recent research studies reported in journals that have investigated applications / extensions of the various theories.
In the end, there’s no quick fix for research, unfortunately – it’s an investigative process and it does take time. Keep in mind that we don’t want a PhD though! To give you a rough idea, 5-10 good academic references, appropriately used and integrated into your literature review and analysis, and properly cited and referenced would probably be very good. Two or three text books and/or a few random web-sites would be considered a very poor effort.