Reasoning with Graph
 Knowledge Representation and Reasoning with Graph Databases
 Reasoning with Graphs
 From Deduction Graphs to Proof Nets
Key Value Store options
 http://googleopensource.blogspot.com/2011/07/leveldbfastpersistentkeyvaluestore.html
 http://stackoverflow.com/questions/6639080/keyvaluestoresuggestion
 BabuDB
BabuDB is an embedded nonrelational database system. Its lean and simple design allows it to persistently store large amounts of keyvalue pairs without the overhead and complexity of similar approaches such as BerkeleyDB.
License: New BSD license, Language: Java
JDBM2 provides HashMap and TreeMap which are backed by disk storage.
License: Apache License 2.0, Language: Java
Banana DB is a selfcontained key/value pair database implemented in Java.
License: Apache License 2.0, Language: Java
I’ve tried BabuDB and JDBM2 and they work fine. BabuDB is a little bit more difficult to set up, but potentially delivers higher performance than JDBM2.
Papers

Knowledge representation and reasonings based on graph homomorphism
 Gram: A Graph Data Model and Query Language
 Tutorial 1: Introducing Graph Data http://www.linkeddatatools.com/introducingrdf
 graph database at sourceforge http://sourceforge.net/projects/graphdb/files/Document/
 Simple implementation of graph database:
 sgdb
 http://ups.savba.sk/~marek/sgdb.html
 simplegdb
 https://simplegdb.svn.sourceforge.net/svnroot/simplegdb/
 http://ups.savba.sk/~marek/papers/sgdbpaper.pdf
 sgdb
 blueprint: https://github.com/tinkerpop/blueprints/wiki
Survey of Graph Database Models
RENZO ANGLES and CLAUDIO GUTIERREZ
Computer Science Department, Universidad de Chile
2. GRAPH DATA MODELING
a graph dbmodel is characterized by:
The data and/or the schema are represented by graphs, or by data structures generalizing the notion of graph (hypergraphs or hypernodes).
 The approach is to model the database directly and entirely as a graph [G¨uting 1994].
 A graph dbmodel is one whose single underlying data structure is a labeled directed graph; the database consists of a single digraph [Levene and Loizou 1995].
 A database schema in this model is a directed graph, where leaves represent data and internal nodes represent connections between the data [Kuper and Vardi 1984].
 Directed labeled graphs are used as the formalism to specify and represent database schemas, instances, and rules [Paredaens et al. 1995].
 In this model, a database is described in terms of a labeled directed graph called schema graph [Kunii 1987].
 A graph dbmodel formalizes the representation of the data structures stored in the databases as a graph [Graves et al. 1995a].
 The schema as well as the instance of an object database is represented by a graph. The nodes of the instance represent the objects of the database [Gyssens et al. 1990].
 Database instances and database schemas are described by certain types of labeled graphs [Hidders 2002].
 The model for data is organized as graphs [Amann and Scholl 1992]. Labeled graphs are used to represent schemas and instances [Hidders and Paredaens 1993].
Data manipulation is expressed by graph transformations [Gyssens et al. 1990], or by operations whose main primitives address directly typical features of graphs, like paths, neighborhoods, subgraphs, graph patterns, connectivity, and statistics about graphs (diameter, centrality, etc.)
A.12 Related Data Models