[1] Spring Object/XML mapping example https://www.mkyong.com/spring3/spring-objectxml-mapping-example/

[2] Mkyong.com https://www.mkyong.com/all-tutorials-on-mkyong-com/

[3] Spring Framework Documentation https://docs.spring.io/spring/docs/current/spring-framework-reference/index.html

[4]* Intro to AspectJ http://www.baeldung.com/aspectj

[5] Data access object (DAO) in Java https://stackoverflow.com/questions/19154202/data-access-object-dao-in-java?noredirect=1&lq=1

[6] view mysql stroed procedure https://stackoverflow.com/questions/1968773/view-stored-procedure-function-definition-in-mysql
SHOW CREATE PROCEDURE check_parts;

[7] MySQL CHECK Constraint Emulation http://www.mysqltutorial.org/basic-mysql-tutorial-aspx/mysql-check-constraint/

[8] New and old ways to emulate CHECK constraints, DOMAIN https://mysqlserverteam.com/new-and-old-ways-to-emulate-check-constraints-domain/

[9] When you should and should NOT use ENUM data type https://dzone.com/articles/when-you-should-and-should-not

[10] 8 Reasons Why MySQL's ENUM Data Type Is Evil http://komlenic.com/244/8-reasons-why-mysqls-enum-data-type-is-evil/

[11] Creating stored procedure and SQLite? https://stackoverflow.com/a/3335202/6498272

[12] What does “unsigned” in MySQL mean and when to use it? https://stackoverflow.com/a/3895705/6498272