Here is the license of Thinking_in_C# by Larry O’Brien and Bruce_Eckel (TCS, p. vi-vii):
Copyright ©2002 Larry O'Brien Source code file from the 1st edition of the book "Thinking in C#."
All rights reserved EXCEPT as allowed by the following statements: You can freely use this file for your own work (personal or commercial), including modifications and distribution in executable form only. Permission is granted to use this file in classroom situations, including its use in presentation materials, as long as the book "Thinking in C#" is cited as the source. Except in classroom situations, you cannot copy and distribute this code; instead, the sole distribution point is http://www.ThinkingIn.Net (and official mirror sites) where it is freely available. You cannot remove this copyright and notice. You cannot distribute modified versions of the source code in this package. You cannot use this file in printed media without the express permission of the author. Larry O’Brien makes no representation about the suitability of this software for any purpose. It is provided "as is" without express or implied warranty of any kind, including any implied warranty of merchantability, fitness for a particular purpose or non-infringement. The entire risk as to the quality and performance of the software is with you. Larry O’Brien, Bruce Eckel, and the publisher shall not be liable for any damages suffered by you or any third party as a result of using or distributing software. In no event will Larry O’Brien, Bruce Eckel or the publisher be liable for any lost revenue, profit, or data, or for direct, indirect, special, consequential, incidental, or punitive damages, however caused and regardless of the theory of liability, arising out of the use of or inability to use software, even if Larry O’Brien, Bruce Eckel and the publisher have been advised of the possibility of such damages. Should the software prove defective, you assume the cost of all necessary servicing, repair, or correction. If you think you've found an error, please submit the correction using the form you will find at www.ThinkingIn.Net. (Please use the same form for non-code errors found in the book.)