1- Alozie,Noney M,Gruber ,David j, Dereski,O. Mary (2012): Promoting 21 st Century Skills in the Science Class Room by Adapting Cookbook Lap Activates :The Case of DNA Extraction of Wheat Germ .American Biology Teacher,74 970,485-489.
2- Bybee,w.,rodger(2010): The Teaching of Science: 21 st Century Perspectives .NSTA Press.
3- Baily ,m.,(2016):Digital citizenship in schools ,international society for technology in education (iste).usa: Washington
4- Brem, K., (2014): Using Critical thinking to Conduct effective Searches of Line Resources, ERIC digest, ED 447199.
5- Carin, A., (2015): Teaching Science through Collaborative Problem Soiving, New York: Merrill, An Imprint of Macmillan Publishing Company.
6- Griffin, P. and Mcgaw, B. (2015): Assessment and Teaching of 21 Century Skills. Victoria: Springer.com/ gp/ book/
7- Hiong, L., (2014): A Conceptual Framework for the Integration of 21 st Century Skills in Biology Education, Research Journal of Applied Sciences, Engineering and Technology,7(16),2976-2983.
8- Ken, K., (2014): 21 st Century Skills, why they Matter, what they are How we get there ?.
http:// www. Innovationalbs.com/resources/kenkay.
9- Lu, Hsin and Lin, peng; (2017): A Study of the Impact of Collaborative Problem Solving Strategies on Student's Performance of Simulation-Based Learning-A case of Network Basic Concepts Course. International journal of information and education Technology, 7(5),361-366.
10- Marchis, Zsolods., (2015): Changing Pre-Service Primary-School teacher's attitude towards Mathematics by collaborative problem Solving - Social and behavioral Sciences,186,174-182.
11- Meihue, Q., and Karen, C, (2016): Game-based and 21 st Century skills: A review of recent research. computers in Human Behavior 63, 50-58 .
12- Mills, Leila., (2015):Collaborative Problem solving in Shared space Retrieved from http:// 0811/742/1103.Y.hp.web.b.ebscohost.com.
13- Pizzini, E., (2015):A Rational for and the Development of a Collaborative Problem Solving Model of Instruction in Science Education, Science Education,73(5),523-534.
14- Saavedra, R.,Anna and opfer.V.Darleen (2012): Learning 21 st Century Skills Requires, 21 st Century Teaching.
http://teacherweb.com/PA/the Campus school of University.
15- Shannon, M., (2016): Implementation of the 4CS of st Century Learning Skills whitin the Blended Coaching Model. Doctor of Education. Pro Quest Database.
16- Stevens,R., (2012): Identifying 21 st Century Capabilities International Journal of Learning and Change, 6 (3),123-137.
17- The National Science Teachers Association (2013): Quality Science Education and 21 st Century Skills.
http://www.nsta.org/about/positions/21 st Century.aspx.
18- http://www.Crinfo.Org/Coreknowledge/ Consensus/building.
19- https://resources.ats2020.eu/resource-details/LITR/ATC21s
20- http://www.direction Service.org/Cadre/Section. CFn# stepsin the collaborative Process.
22- http://www.novitasacademy.org/about-us1/coollaborative problem Solving.
23- http:// digital citizenship.net/Nine_Elements.htm/
www.mcit.gov.eg/AR/Digital Citizen ship/Internet_Safety/Education.