I am reading to find the difference between firms' competitiveness and competitive advantage, but these two look like same to me. Would please you suggest any reading materials where I can find the actual difference between the two.
The competitiveness and competitive advantage are very close as far as meaning is concerned. In assessment of both you need to compare company's products (or services) with those of competitors. Competitiveness is more inward looking.
Competitiveness is how an organization positions or ranks in an industry; when compared with other firms in the same industry. As an example Toyota versus Ford might have the same degree of competitiveness or even market shares.
Competitive advantage is the firms internal strengths that provides or results in that specific degree of competiveness. As an example, supply chain structure might be the competitive advantage of Toyota while Ford might have the competitive advantage of affordabilitu.