Pls. Help me answer the following questions, cite the sources used. This is Labor Law Employment in the Philippines based.

Employment may be LAWFULLY terminated by the employer or by the employee himself. The employee may terminate his employment through resignation. The employer may lawfully terminate the employment of the employee for just cause or authorized cause.

Questions:

1. What are the requisites for RESIGNATION under our laws? (Philippines' laws)
2. What are the JUST CAUSES for terminating an employee? Briefly explain each. (Based on the Philippines laws)
3. What are the AUTHORIZED CAUSES for terminating an employee? Briefly explain each. (Based on Phil.Laws)

Cite your sources.