We are studying ways to provide automated, context-specific links (called "infobuttons") between clinical information systems (CIS) and other information resources available on the World Wide Web. As part of this work, we observed the information needs that arose when clinicians used a CIS and we classified those needs into generic questions. We then sought general methods for accessing information resources to answer the questions. For each generic question, we identified a satisfactory resource and then developed a method for retrieving from it the information relevant to the question. We then studied these methods to characterize them into general approaches. We identified six general approaches and describe them in detail. These approaches range in complexity from simple, hard-coded links to intelligent agents and calculators. Web-based information resources can be exploited using a relatively small number of methods, although the specific methods require custom solutions. Standard methods for accessing Web-based resources would simplify the task of linking to CISs.