Just finished reading "Head First C". Where do I go from here?

Just finished reading "Head First C". Where do I go from here?

The title pretty much entitles it. I just finished reading the book Head
First C. I would like to continue in the right path. And not waste my time
doing supplementary studies. On page 552 they state some popular
books/reference material. These are:
Brian W. Kernighan and Dennis M. Ritchie, The C Programming Language
(Prentice Hall; ISBN 978-0-131-10362-7)
This is the book that defined the original C programming language, and
almost every C programmer on Earth has a copy.
Samuel P. Harbison and Guy L. Steele Jr., C: A Reference Manual
(Prentice Hall; ISBN 978-0-130-89592-9)
This is an excellent C reference book that you will want by your side as
you code.
Peter van der Linden, Expert C Programming
(Prentice Hall; ISBN 978-0-131-77429-2)
For more advanced programming, see Peter van der Linden's excellent book.
This book outlines the practical details of C development.
Steve Oualline, Practical C Programming
(O'Reilly; ISBN 978-1-565-92306-5)
Websites
For standards information, see:
http://pubs.opengroup.org/onlinepubs/9699919799/
For additional C coding tutorials, see:
http://www.cprogramming.com/
For general reference information, see:
http://www.cprogrammingreference.com/
For a general C programming tutorial, see:
http://www.crasseux.com/books/ctutorial/
I don't know which of these to choose from, should I go for all of them?
RIP my social life..
Could anyone help me pick? I would love to get in to openGL programming.
But i'm afraid my knowledge from reading a single book on the language is
too small. Could any knowledgeable member give me some advice? It would
really be appreciated!