1. A method of cross-referencing data within a searchable database on a computer device including a memory device, wherein a directory tree structure is stored on the memory device and includes nodes and branches comprising links between the nodes, the directory tree structure including a designated category for each node, the method comprising: generating at least two data pointers corresponding to a specific node, wherein a first data pointer of the at least two data pointers points from the specific node to a first item of data within the searchable database via a first navigation path through the directory tree structure, wherein a second data pointer of the at least two data pointers points from the specific node to a second item of data within the searchable database via a second navigation path through the directory tree structure, and wherein the first and second items of data are related to the designated category of the specific node; and generating at least one node pointer, wherein the at least one node pointer points from a first node located in the first navigation path to a second node located in the second navigation path, wherein the first navigation path is different from the second navigation path, wherein the first node and the second node are each different from the specific node; wherein, at each node within the directory tree structure, the searchable database is searchable by selecting any data pointers or node pointers corresponding to the node or by performing one or more of a keyword search, a hierarchical search, a dichotomous key search, and a parametric search.