The Practical Guide to building an online marketplace is written by Christóbal Gracia and Juho Makkonen. All articles are available in Marketplace Academy and as a book, Lean Marketplace. Article available at:
How to design your marketplace transaction flow, Juho MakkonenSources and further reading: 

How to choose the right marketplace business model, Marketplace Academy
Marketplace payments 1: Compare payment providers, Marketplace Academy 
Marketplace payments 2: What are the key features of marketplace payment solutions?, Marketplace Academy 
Marketplace payments 3: Costs, integration, and more things to consider, Marketplace Academy 

Fundamental Guidelines Of E-Commerce Checkout Design, Christian Holst 

E-Commerce Checkout Usability, Baymard 

Nine user experience lessons travel sites can learn from Airbnb, Graham Charlton 

How To Guard Your Online Marketplace Against Fraudsters, Forbes 

Marketplace financial crime – how to avoid the risks, Marketplace Academy 

How to discourage people from going around your payment system Want to delay payments? Here’s what you need to know about escrow, WePay 

Global payment methods guide, Adyen
The Marketplace Academy Podcast is hosted and narrated by Katri Antikainen.Learn more about building a marketplace at www.sharetribe.com/academy/.Looking to build a marketplace of your own? Visit www.sharetribe.com!