The intermetallic family R5T4 (R = rare earth, T = Si or Ge) exhibit a wide range of magnetic phenomena (eg., magnetic order, GMR, and enhanced magnetocaloric effect) which are extremely sensitive to the arrangement of, and bonding between, unit layers. While most magnetic ordering temperatures range from tens to hundreds of degrees K, Yb5Ge4 is a mixed valence antiferromagnet with TN = 1.8 K; the nearly isostructural ternary derivative Yb4LiGe4 appears to be paramagnetic to much lower temperatures. We propose to search for strongly correlated behavior in these systems. In order to characterize the low-temperature ground state we propose to conduct zero and longitudinal field studies down to 50 mK for both the Yb5Ge4, and Yb4LiGe4, which may be a heavy fermion system (based on T > 3K specific heat measurements) in close proximity to a quantum phase transition.