American Jurisprudence 2d, or AmJur, is a legal encyclopedia available on Westlaw.  It is national in coverage and provides descriptive overviews of an area of law.  Organized alphabetically and topically, it may be searched with keywords

Relevant Entries:

Labor and Labor Relations ► V. Employer Unfair Labor Practices ► B. Discrimination on Basis of Union Membership

Labor and Labor Relations ► VI. Union Unfair Labor Practices

American Law Reports Annotations are available on Westlaw and Lexis.  These narrow, issue or case driven reports, provide descriptive and well-researched annotations.  

Some relevant ALR annotations include:

Lawfulness of strike to compel collective bargaining, 20 A.L.R. 1513 (Originally published in 1922)

Collective labor agreements, 95 A.L.R. 10 (Originally published in 1935)

Deduction or collection of labor union dues from wages of employees, 135 A.L.R. 507 (Originally published in 1941)

Rights and remedies of workmen blacklisted by labor union, 173 A.L.R. 1401 (Originally published in 1948)

Federal Procedure, Lawyer's Edition gives you guidance for every aspect of procedures before federal courts and administrative agencies. It is available on Westlaw. Relevant entries include: 

Chapter 52: Labor and Labor Relations 

IV. NLRB Representation Proceedings

VII. Union Regulation Proceedings and Reporting/Disclosure Enforcement Procedures