SOURCE OF INFORMATION: In the last few years there has been a vast growth in the development of information system and the generation of information. Along with this development comes the real problem of finding out relevant information quickly and easily. This problem can be solved by proper filing system and record keeping.
In general there are three principal sources of scientific information:
1. Original papers published in learned journals (primary sources).
2. Compilation of data on specific subjects (secondary sources)
3. Text books (tertiary sources)