Ontology : being best defined as answering the Foundational Question in First Philosophy and Metaphysics "Ti to On " Greek : What actually exists or has being ?; and involving the secondary Question of how we obtain certainty of this must include and involve what is now termed 'Epistemology' or the Theory of how Knowledge and certainty is obtained (though some disagree wanting to separate the fields). The Older School being Symbolic analysis of language and the newer being Connectivist theory using the understandings built up by computing and programming to understand the mind in its functions of decision making . Another Area of necessary research is in What is now termed "Mereology" the possible Complex relationship of parts to a unified Whole in which Springer has done recent research. All the More Important in Search of Unified Theory following the revolution of Einstein's thought in Science . The Universe as a Unified Event in Timespace and involving the unity and interconvertibility of matter and energy. I am Reading Harris though written in 1965 was an early wake up call as to the Revolution of Relativity and Nuclear Physics which necessitated a Radical Revision of classical Metaphysics, and Has much to do with Wholism in Mereology.

Harris, Errol (1965) The Foundations of Metaphysics in Science

London , George Allen and Unwin Ltd BD111.H274

Chapter 2. The Physical world

Responding in 1965 to the Challenge of Physics to Classical Philosophical Metaphysics, the South African Philosopher Harris sought not to remind science of its early origins in Metaphysics. But of the need for a Revolutionary revision of Metaphysics drawing on Science. In the Book ‘The Foundations of Metaphysics in Science’ he writes:

“The twentieth-century revolution in physics presents us with a conception of physical nature so radically different from that entertained by classical physics that the philosophical outlook conditioned by the latter is no longer viable either as a metaphysical theory or as a tacit presupposition of other sciences”.

After considering the two main phases of this “revolution” Relativity, and Quantum Subatomic Physics Harris went on to state.

“The physical world is thus seen as a macroscopic totality encapsulating within it microscopic totalities all constituted on similar principles of unified order. It is a complex system to which the constituent elements are integral and mutually formative. In the light of this conception any talk of ‘atomic facts’ is wholly incongruous and the sort of logic based on mutually independent propositions is obviously inappropriate”.

Our best Understandings of the Universe, of Universal and Eternal Truth have taken a Quantum Leap in the Light of Einstein, who must be counted not only as a Genius Scholar of Physics but of Metaphysics. Foundational Metaphysics in Aristotelian, and Scholastic First Philosophy, whilst it was the historical beginnings of the Trunk supporting the Tree of the Academy in all its branches of Scientific speciality now needing to draw from them to grow into its mature and adapted form. We are no longer dealing with a Universe “With Angels in the Architecture, Spinning in Infinity”* but bounded Universal Timespace from its Early Expansion, informing the Parent Branches of the Tree: Cosmology; Ontology; and Teleology. Matter and Energy as Primary Complementary opposites, United Integrated and Interconvertible. Forces conceived in a Unified Field, in the Unfinished project of Einstein.

HI!

I recommend that you check up Luciano Floridi, professor in Philosophy and Ethics of Information at Oxford, and his "Informational Structural Realism", which is presently in the making. Floridi is building a new prima philosophia from scratch to reflect a time when informaiton and communication technologies are being "inscribed" into our world, and we increasingly perceive the world informationally, and ontology and epistemology becomes a lot part of the same, although not identical. Begin with checking up papers on his RG account, or http://www.philosophyofinformation.net/ or if you want to go for the heavy stuff at once, his book "Philosophy of Information!. he has a lot of lectures, short and long, on his youtube channel as well. 

Novatorov, Edouard, Critical Issues of Methodological Pluralism in Marketing Science: The Case of Development Non-Profit Marketing Concept (June 15, 2013). Available at SSRN: https://ssrn.com/abstract=2279799 or http://dx.doi.org/10.2139/ssrn.2279799