RFC 1777 - Lightweight Directory Access Protocol
RFC 1778 - The String Representation of Standard Attribute Syntaxes
RFC 1779 - A String Representation of Distinguished Names
RFC 1823 - The LDAP Application Program Interface
RFC 2251 - Lightweight Directory Access Protocol (v3)
RFC 2252 - LDAPv3: Attribute Syntax Definitions
RFC 2253 - LDAPv3: UTF-8 String Representation of Distinguished Names
RFC 2254 - The String Representation of LDAP Search Filters
RFC 2255 - The LDAP URL Format
RFC 2256 - A Summary of the X.500(96) User Schema for use with LDAPv3
RFC 2307 - An Approach for Using LDAP as a Network Information Service
RFC 2696 - LDAP Control Extension for Simple Paged Results Manipulation
RFC 2849 - The LDAP Data Interchange Format (LDIF) - Technical Specification
RFC 2891 - LDAP Control Extension for Server Side Sorting of Search Results
RFC 3296 - Named Subordinate References in LDAP Directories

Expired but used Draft:
ldapext-ldapv3-vlv-04: LDAP Extensions for Scrolling View Browsing of Search Results