TITLE: LDPC codes construction
QUESTION [5 upvotes]: According to Google Scholar original Gallager's article Low-density parity-check codes is cited more than 10000 times. It looks scary for non-experts.
I suspect that the number of algorithms for constructing good sparse matrices for LDPC-codes is much less than 10000.  Is there any survey which contains description of such algorithms? 
Basically I'm interested in explicit constructions based on number theory methods.

REPLY [3 votes]: Ryan and Lin's Channel Codes has several chapters (computer-based, finite geometries, finite fields, combinatorial designs) devoted to various constructions of LDPC codes, as well as a chapter devoted to nonbinary codes that also details constructions for that case.