Content Writing / SEO Friendly Articles

I am looking for someone to write 50 articles / blog posts based on several topics within the digital marketing industry. We are a digital marketing business who is looking to grow over the next few months and with that growth comes the need for new content and copy for our websites. The articles need to be 350-500 words long each and based on several topics to include: SEO Social Media Marketing Video Marketing Content Web Design Adobe Business Catalyst The full list of subjects will be provided to the successful applicant. The articles need to be written with SEO in mind and be keyword rich, designed to help drive traffic to our main website and be easily read and enjoyed. We are looking for a long term writer with 30-50 articles required every 6-8 weeks. This is an initial project to find the right writer for us.