These links should be helpful.

http://www.professional-counselling.com/types-of-nonverbal-communication.html#.VQmy6454rYg

http://www.yousaytoo.com/importance-of-non-verbal-communication/2435699

http://2012books.lardbucket.org/books/sociology-brief-edition-v1.1/s05-02-the-elements-of-culture.html

http://2012books.lardbucket.org/books/a-primer-on-communication-studies/s04-nonverbal-communication.html

http://www.slideshare.net/StuartGrenvillePrice/signs-symbols-and-visual-codes

https://prezi.com/wgvz2j6zqegb/non-verbal-symbols/

http://faculty.buffalostate.edu/smithrd/UAE%20Communication/Unit2.pdf

Thank you Adukwu 

http://eric.ed.gov/?id=ED069128

http://psycnet.apa.org/psycinfo/1973-24485-010

Here is an example of a specific hand signal (gesture) I am working on (non verbal communication). 

Conference Paper Réflexion sur l’impact de la communication non-verbale inter...

 Thank you  Chaminda and Marie, now I can start on my literature review.  

interesting field and important question. I would like to Support you. Please can you specify your question? It will be easier for me to answer. Though I more often can Support you with German literature. By the way there is a lot being done and writtenin German. :-) I myself just wrote an introduction into Body language and nonverbal communication in German. It will be translated into CHinese and published at the end of the year. So....just waiting for your answer :-)

@Ulrich, my question is Understanding  the use of hand sign (non verbal) by commuters in South Africa (its not definite but key terms like hand sign, commuters are fixed ) because am pursuing Honours my specif research locations are two townships to keep it small and manageable. Any German literature that has worked along the lines of nonverbal or verbal communication in the transportation system will be off great help or broader done research related to communication strategies will be a pleasure to read. 

@ Flora I can answer to you later in the afternoon. Wish you a nice day :-)

Dear Flora,

I just found out that some of my colleagues also have published a lot in English, so it’s easier for you to read. ;-)

All the three of them are international well known specialists on gesture study and research.

I think it is supportive enough if I just the names of my colleagues to you. If you have a look via google you’ll find specific papers on specific aspects. So you better have a look by yourself to decide which is appropriate for you.

The colleagues are:

Simone Pika

Hedda Lausberg

Judith Holler

If you can read German I can send to you the specific chapter on gesture from my book “Introduction to body-language and nonverbal communication”. But I have to warn you: It’s in German ;-)

 Wish you a good job and success

In Communications theory, American sign Language and other sign languages that attach specific meaning to gestures is considered to be VERBAL.  It does not use sound or spoken words, but the gestures convey vocabulary and grammar.

@ Marek thus why some authors who have published from communication point of view do not agree that there is such thing as verbal or nonverbal communication but simply " communication" 

Kendon and McNeil are two linguistic anthropologist Gesture specialists that you'd be remiss overlooking

can you put your question a bit more pecisely? :-) Otherwise you would be overwhelmed by possible answers and literature. :-)