R. Divekar, N. Salvi, S. Agha, and S. Tiwari. International Journal on Recent and Innovation Trends in Computing and Communication, 3 (3):
1468--1471(March 2015)
D. Jonassen, K. Beissner, and M. Yacci. LEA. Lawrence Erlbaum Associates, Hillsdale, NJ, (1993)David H. Jonassen, Katherine Beissner, Michael Yacci. Includes bibliographical
references and index. $5GBV.