a.
Harvard Referencing a book typically goes: [Author Surname], [Author Initial]. ([Year Published]). [Title]. ed. [City]: [Publisher], p.[Pages Used].
All you have to do is fill in the gaps:
Byrne, MM (2010). Economics and Management Sciences . Pretoria: University of South Africa. p.[Pages Used].
I don't know which pages you are referencing, so I included the template, which you can easily replace. You could always comment the pages, in which case I can do it for you.
b.
[Author Surname], [Author Initial.] ([Year Published]) [Title].[Publication Title], [Volume number]([Issue number]), [Pages Used].
All you have to do now is fill in the gaps:
Nuna, T and Walker, S . (2014). Research methods in Economics.Journal for Economics. 2 (3), 113 - 150.