This can be found at http://gslc.genetics.utah.edu/units/basics/blood/types.cfm (from Univeristy of Utah) along with an article about blood typing.
What kind of blood will your body take safely?
Chart Of A-B-O Blood Donor & Recipient Compatibility
Rh Positive (Rh+) and Negative (Rh-) Blood Types
The Rh (+/-) factor is inherited separately from the ABO blood types. Similarly to the masking effect of the O gene in ABO blood types, the Rh negative (Rh-) gene is also masked by the presence of a Rh positive (Rh+) genotype. Therefore, a person may have a Rh + blood type and can still have an Rh - gene (See the chart below). Furthermore, 2 parents with Rh + blood types can have a child with Rh - blood type.