Documentación de PHP: https://www.php.net/docs.php
PEAR :: The PHP Extension and Application Repository: https://pear.php.net/
Pear::DB Database Abstraction Layer: https://pear.php.net/package/DB
DBC Technology: https://java.sun.com/products/jdbc/
MySQL Connector/J: https://dev.mysql.com/downloads/connector/j
PostgreSQL JDBC Driver: https://jdbc.postgresql.org/
